Solanum Section Geminata (Solanaceae) (Flora Neotropica Monograph No. 84)

Organization for Flora Neotropica Solanum Section Geminata (Solanaceae) Author(s): Sandra Knapp Source: Flora Neotropic...

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Organization for Flora Neotropica

Solanum Section Geminata (Solanaceae) Author(s): Sandra Knapp Source: Flora Neotropica, Vol. 84, Solanum Section Geminata (Solanaceae) (Jul. 30, 2002), pp. 1404 Published by: New York Botanical Garden Press on behalf of Organization for Flora Neotropica Stable URL: http://www.jstor.org/stable/4393908 Accessed: 21/10/2008 12:36 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showPublisher?publisherCode=nybg. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. JSTOR is a not-for-profit organization founded in 1995 to build trusted digital archives for scholarship. We work with the scholarly community to preserve their work and the materials they rely upon, and to build a common research platform that promotes the discovery and use of these resources. For more information about JSTOR, please contact [email protected].

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FLORA NEOTROPICA MONOGRAPH 84

SOLANUMSECTION GEMINATA(SOLANACEAE) SANDRA KNAPP

FLOR........... NEOTROPICA> 'toic

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N AP/C/WON

Publishedfor Organization for Flora Neotropica by The New York Botanical Garden Bronx, New York

Issued 30 July 2002

? 2002 by The New YorkBotanical Garden All rights reserved. Published by The New YorkBotanical Garden Bronx, NY 10458

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Library of Congress Cataloging-in-Publication Data Flora neotropica.- Monographno. 1 - New York:Published for Organizationfor FloraNeotropica by The New York Botanical Garden, 1968v.: ill.; 26 cm.

Irregular. Eachissue has distinctivetitle. Separatelycataloguedand classified in LC before monographno. 40. ISSN 0071-5794 = Flora neotropica. 1. Botany - Latin America- Classification - Collected works. 2. Botany - Tropics- Classification- Collected works. 3. Botany Classification- Collected works. I. Organizationfor FloraNeotropica. II. New YorkBotanical Garden. QK205.F58 Libraryof Congress ISBN 0-89327-441-0

581.98'012-dcl9

85-647083

[8508]

02 03 04 05 06 07 08 09 10/98765432

1

SOLANUMSECTION GEMINATA (SOLANACEAE) SANDRA KNAPP

CONTENTS 2 Abstract/Resumen ........................................................................................................ Introduction....................................................................................................................... 3 4 History of Classification of Solanum................................................ Nomenclaturaland TaxonomicHistory of Section Geminata ........................................... 5 Morphology................................................. 8 Habit .............................................................................................................................. 8 Stems .................................................................................................. 8 . Leaves .......................................................................................................................... 10 Inflorescences.............................................................................................................. 10 Flowers ........................................................................................................................ 11 Fruits ............................................................................................................................ 12 Seeds ............................................................................................................................ 15 Trichomes .................................................................................................................... 15 Chromosomes .............................................................................................................. 22 Ecology andNaturalHistory ............................................................................................ 22 Habitatsand Distribution......................................................................................... 22 Pollination ..................................................................................................................... 25 FruitDispersal .............................................................................................................. 28 Sex Expression............................................................................................................. 29 fHerbivores.................................................................................................................... 31 Species Groupsand Species Concepts............................................................................. 32 Species Groups ............................................................................................................ 32 Species Concepts..........................................................................................................32 Taxonomic Treatment ......................................................... 38 Artificial Key to Woody, Similar Groupsof Non-Spiny Solanums ............................ 39 Artificial Key to the Species Groups............................................................................ 40 Synoptic Key to the Species ......................................................................................... 42 l. Solainumoblongifoliumspecies group ......................................................................43 II. Solanumlpseudocapsicum species group ................................................................54 1II.Solanumn ntidumspecies group...............................................................................69 IV.Solanum leucocarpon species group .................................................................... 136 V. Solanum nutans species group...............................................................152 VI. Solanum amblophyllumspecies group ................................................................ 165 VII. Solanumdeflexiflorumspecies group ................................................................. 179 VIII. Solanum arborelum species group .................................................................... 194 IX. Solanumunifoliatumspecies group ..................................................................... 223 X . Solanumrob stifrons species group ............................................. ........................ 235 XI. Solanumnarcoticosmnum species group .............................................................. 247 XII. Solanum nigricans species group....................................................................... 254 X III. Solanum arenarium species group ................................................................... 273 XIV. Solanumsessile species group........................................................................... 282 XV. Solaniumconfine species group ........................................................................... 311

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FLORANEOTROPICA XV I. Solanum dolosum species group....................................................................... 350 IncertaeSedis ........................................................................................................... . . . 356 New Species Added in Proof ..................................................................................... 361 DoubtfulNames ............................................................................................................. 363 Excluded Species ............................................................................................................ 364 Acknowledgments .......................................................................................................... 368 Literature Cited ...............................................................................................................36 9 Numerical List of Taxa ................................................................................................... 375 Exsiccatae ....................................................................................................................... 377 Index of Scientific Names .............................................................................................. 399 Appendices .....................................................................................................................403

ABSTRACT Knapp, Sandra (Departmentof Botany,The NaturalHistoryMuseum,CromwellRoad, London SW7 5BD, United Kingdom).Solanumsection Geminatas.l. [sections Geminata, Pseudocapsicum, Holophylla pro parte, and Indubitaria pro parte] (Solanaceae). Flora Neotropica Monograph84: i-iv + 1-404. 2002. -Solanum section Geminatas.l. (Solanaceae) includes about 126 species of shrubsand small trees native to the Neotropics. Membersof the sectionrangefromnorthernMexico andthe WestIndiesthroughoutSouthAmerica to UruguayandnorthernArgentina.A single species is nativeto the Paleotropics,fromChina to tropicalAustralia,and is also unusualin the group in being polyploid. Most species are shrubsor small treelets found in light gaps or along streamsin primaryforest understory.A few species arecommonin second growthforestsin manyforesttypes. The sectionas treated here containsspecies with both simple andbranchedtrichomes.It is clearfromthis studythat the trichomecharacterstraditionallyused to differentiatesectionsofSolanumaretoo variable to be of use in sect. Geminata. Some species traditionallytreated as members of sects. Pseudocapsicum,Indubitaria,andHolophyllaare includedin the monograph,as those sections as traditionallyconstitutedareartificialgroupingsof apparentlyunrelatedtaxa. The monographtreatstaxonomic history,morphology,ecology, and naturalhistory of Solanumsect. Geminatas.l. One hundredtwenty-six species arerecognizedin this treatment and fourinsufficientlyknowntaxa arediscussedin contextwith theirputativerelatives.The section has been dividedinto 16 species groupsto facilitateidentificationandfuturein-depth phylogenetic study. Species groups are defined using largely charactersof: 1) sympodial structure,2) leaf shape,3) trichomemorphology,4) inflorescencemorphology,5) pedicel scar type, 6) fruitingpedicel morphology,and 7) seed morphology.A fundamentaldifferencein seed morphologyappearsto separatethe section into two broadgroups:those species groups with flattenedreniform seeds typical of those found elsewhere in the family, and species groups with unusual ovoid reniformseeds found only in sect. Geminata.All typification andnomenclaturalissues pertainingto the section andits componentspecies arecomprehensively examined. Section Geminatas.l. may not be monophyletic,but knowledge aboutrelated groups is scanty and a definitivejudgment cannotbe made at present. Extensiveecologicaldataareincludedon pollinationandherbivory.PollinationinSolanunm sect. Geminatais similarto thatobservedthroughoutthe genus. Femalebees of severalfamilies vibratethe poricidalanthersandextractpollen. Specializedherbivoresof membersof the section arebeetles of the family Chrysomelidaeandnymphalidbutterfliesof the subfamily Ithomiinae.Larvaeof relativelyphylogenetically"advanced"butterfliesfeed on species in the section, but specific host/herbivoretrackingis not apparent.Futurecladistic studies of both hosts and herbivoresmay reveal patternsin these relationships.

RESUMEN Knapp, Sandra (Departmentof Botany,The NaturalHistoryMuseum,CromwellRoad, London SW7 5BD, United Kingdom).Solanumsection Geminatas.l. [sections Geminata, Pseudocapsicum, Holophyllaproparte,andIndubitaria proparte](Solanaceae).FloraNeotropica

INTRODUCTION

3

Monograph84: i-iv + 1-404. 2002. -Solanum section Geminatas.l. (Solanaceae)incluye alrededorde 126 especies de arbustosy pequefiosarbolesnativos del Neotr6pico.Miembros de la secci6n se distribuyendesde Mexico y las Antillas, a trav6sde Sudam6rica,hastaUruguay y el nortede Argentina.Una sola especie es nativadel Paleotr6pico,desde Chinahasta Australia,siendoinusualen el grupopor serademaspoliploide.La mayoriade las especies son arbolespequefiosque crecen en claros o a lo largo de arroyos,en el sotosbosquede bosques primarios.Pocasespeciesson comunesen bosquessecundariosde diversostipos.La secci6n,en la formaaquitratada,contieneespeciescon ambostiposde tricomas,simplesy ramificados.De esteestudioresultaclaroquelos caracteres deltricoma,tradicionalmente utilizadosparadiferenciar secciones de Solanum,son demasiadovariablesparaser empleadosen la secci6n Geminata. tratadascomo miembrosde las seccionesPseudocapsicum, Algunasespecies,tradicionalmente Indubitariay Holophylla, son incluidas en la monografia,ya que estas secciones estaban tradicionalmenteconstituidasen agrupacionesartificialesde taxasin relaci6naparentente. Lamonografiatratala historiataxon6mica,morfologia,ecologiae historianaturaldel genero Solanumsecci6n Geminatas.l. Cientoveintiseis especies son reconocidasen el tratamientoy cuatrotaxones, insuficientementeconocidos, son discutidos en contexto con sus parientes putativos.Lasecci6nha sidodivididaen 16gruposde especies,amodo de facilitarsuidentificaci6n y un futuroestudio filogen6tico profundo.Los gruposde especies son definidos utilizando fundamentalmente caracteresde: 1) estructurasimpodial,2) formade la hoja,3) morfologiade los tricomas,4) morfologiade la inflorescencia,5) tipo de cicatrizdel pedicelo, 6) morfologia del pedicelofrutal,y 7) morfologiade la semilla.Unadiferenciafundamentalen la formade las semillas parecesepararla secci6n en dos grandesgrupos:un grupode especies con semillas reniformesy aplanadas, en la familia;y otrogrupode especiesconsemillas tipicamenteencontradas ovoide-reniformes,inusuales,encontradass6lo en la secci6n Geminata.Son tratadosin extenso todaslas cuestionesnomenclaturalesy de tipificaci6nrelacionadascon la secci6n y sus especies componentes.La secci6nGeminatapodriano sermonofiletica,peroel conocimiento sobregruposafines es todaviaescaso y por el momentono puede haberunjuicio definitivo. Se incluyenextensosdatosecol6gicos sobrepolinizaciony herbivorismo.Lapolinizaci6n en Solanumsecci6n Geminataes similar a lo observado en el genero. Abejas hembrasde variasfamiliashacenvibrarlasanterasporicidas,extrayendoasiel polen.Herbivorosespecializados de miembros de la secci6n son escarabajospertenecientes a la familia Chrysomelidaey mariposas de la subfamilia Ithomiinae. Larvas de mariposas, relativamente avanzadas se alimentande especiesde la secci6n,peroaparentemente no hayunarelaci6n filogeneticamente, especifica herbivoro/huesped.Futurosestudios cladisticos de ambos, herbivoroy hu6sped, podrianrevelarrelaciones de este tipo.

INTRODUCTION SolanumsectionGeminata(G. Don) Walp.,with 126 species as treatedhere, is one of the largestsections of the extremelylargeplantgenusSolanum.Solanumhas not been comprehensivelymonographedsince the De CandolleProdromus(Dunal, 1852). In his treatmentof the group,Dunal(1852) included37 species. Latercontributionsby Van Heurck& Miiller-Argovius(1870), Morton(1944), and especially by the prolific German botanistGeorgBitter(1913, 1916, 1919a, 1920a, 1920b, 1922) greatlyincreasedthis number.Manynew species now placed in sect. Geminatas.l. were described,but no attemptwas madeto determinerelationshipsor synonymies in the section.The sectionhas been considered difficult,andspecies arevery similarmorphologically; uniformon the theyhavebeendescribedas "remarkably herbariumsheet" (D'Arcy, 1973). The authorsof two CentralAmericanfloristic treatments(D'Arcy, 1973; Gentry& Standley,1974)triedto sortoutnomenclature

and synonymyin the section, but since the greatdiversity in sect. Geminataoccurs on the easternslopes of the Andes and in the Amazon basin, their attempts, thoughlaudable,treatonly a small fractionof the species in the group. The goals of this study were twofold: first to provide a monographof the group, solving nomenclaturaldifficulties and clarifying species identities,and second to breakthis large andunwieldy group into smaller, monophyletic subgroupssuitable forfuturein-depthstudyandphylogeneticanalysis.The techniquesI have used have been for the most partthe traditionalones of systematicbotanists,examinationand analysis of the comparativemorphologyof herbarium specimens, but I have placed much emphasis on the observationof the species in theirnative habitats.This has been very importantin my eventualunderstanding of relationshipsin the group,and is crucialto the solving of problems in this complex and extremely large section of Solanum.

FLORA NEOTROPICA

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HISTORY OF CLASSIFICATION SOLANUM

OF

Solanumwas one of Linnaeus' largergenera,with 23 species described in the first edition of Species Plantarum(1753). The species describedin thatwork arelargelyEuropeanorAfrican;manyof theexotic ones were known only fromcultivation.The late eighteenth andearlynineteenthcenturiesweretimesof exploration, in theAmericas(Steam,1968;Steele, 1964), particularly andplants collected on expeditions flooded European herbaria.In 1813,Michel-FelixDunal'sthesis,a worldwide monographof thegenus,included235 species.The synopsis (Dunal, 1816) of his never completed second edition included 321 species, of which many of the additionalspecies were collected by Alexandervon Humboldtand Aimee Bonpland in tropicalAmerica. GeorgeDon (1837) enumeratedanddescribed406 species of Solainum.G. G. Walpers(1844) followed Don's general system and listed 435 species and an additional 72 for which he had incomplete information. The last worldwide treatmentof Solanumwas that of Dunal(1852) forAlphonsede Candolle'sProdromus andby thattime the numberof species hadrisento 900. This increase largely reflected the enormousincrease in collections fromtropicalAmerica. Since 1852,manynew specieshavebeendiscovered anddescribed,bringingthe numberof namesin the genus to between 3000 and 5000. The numberof"good" species this representsis difficultto assess, as the genus has grown to proportionsunmanageablefor a single Withprobably1500to 2000 validspecies, monographer. Solanumis one of the largestgeneraof floweringplants. Since there exist so many species of Solanum, comprehensivemonographictreatmentof the entiregenus is problematicif not impossible, andtaxonomistshave concentratedon smaller groupswithin the genus. Linneaus(1753) dividedthe genus into two groups, the Iliermia, or unarmedspecies, and the Spinosa, or armedspecies. Dunal (1813, 1816) divided the genus similarly. His categories were Inermia, or unarmed solanums, and Aculeata, or armed solanums. In the Prodromus(1852) he divided Solanum into two sections ("sectio") which were basically the same as his earlier divisions. He named these Pachystemonum, species with stout, cylindricalanthersandno prickles, and Leptostemonum,species with attenuateanthers, trichomes,andoftenwithprickles(see TableI forDunal's characterizationof the groups). Generaltreatmentsof the entire genus since Dunal's 1852 work have been relativelyfew andlimitedto arrangements ofinfrageneric taxa. Subsequentworkershave divided the genus into subgenera and called the groupings at the next rank

below sections.Fora review of sectionalnomenclature in Solanum, see D'Arcy (1972) and Knapp (1983). Seithe (1962), building upon the voluminous work of GeorgBitter(see bibliographyin Weber,1928) andher own studiesof hairmorphologyin the genus, proposed a classificationfor Solanumbased largelyon trichome types.Thetwo majordivisionsin herclassificationwere the stellate-haired solanums (chorus subgenerum inpartto Dunal'sAculeata), Stellatipilum,corresponding and the simple- and branched-hairedsolanums (chorus subgenerumSolanum).Danert(1967, 1970), using his own workon the developmentof branchingpatterns in the genus and family,proposeda subgenericclassificationtakingintoaccountthesecharacters.Gilli (1970) provided a key to the groupingsof Seithe (1962), but did not propose any new re-arrangementsof taxa. D'Arcy (1972) lectotypifiedall of the existing subdivisions of Solanum,andproposeda provisionalconspectus of the genus. This treatmentis now thatmost commonly used by presentSolanumworkers.He divided the genus into seven subgenera(see Table II) and 52 sections, based on charactershe felt were more realistic than those used in the past. Of these systems of classification, only Seithe's (1962) specified the species to be includedin eachof the subgroupings.D'Arcy (1972) used and cited only the type or lectotype species of each section, andplacing a non-type species in his systemis difficult,if not impossible.Whalen(1984) provideda conspectus for the spiny solanums(subgenus Leptostemonum),in which he divided them into speciesgroupsandlistedthe componentspecies in each group. D'Arcy (1991) assessed revisionary work in Solainumandpresentedan identicalsubgenericscheme, the only differencebeing the replacementof the name subgenus Brevantherumwith subgenus Minon. Nee (1999) has divided the genus (treatingonly the New Worldtaxa) into three subgenerausing charactersof andinflorescencemorphology pubescence,architecture, (see TableII). Componentneotropicalspecies in each section or subdivisionare listed, makingNee's (1999) treatmentan extremelyuseful startingpoint for future work in Solanum. A comparisonof D'Arcy's (1972) and Nee's (1999) systems is presentedin Table II. Relationshipsof subgenericgroupswithinSolanum are currentlybeing investigated using the techniques of molecular systematics (Olmstead& Palmer, 1991, 1997; Spooneret al., 1993; Bruneauet al., 1995;Bohs & Olmstead, 1997, 1999). The use of these tools to identify monophyletic groups within Solanumnwill greatly facilitate futuremonographicwork. Although very few (currentlyonly about30 of some 1000-2000 species) have been analyzed,interestingpatternsof relationship are beginning to emerge. Clearly mono-

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HISTORY OF CLASSIFICATION OF SOLANUM

Table I Classification of Solanum abbreviated from Dunal (1852). Only the two major sectional groupings and the portion of the classification pertaining to section Geminata are included. Symbols are those of Dunal (1852) and are indicative of rank within his system Sectio I. Pachystemonum "Antheraebreviores, crassiores, cylindrico-vel ovato-ellipticae, nec elongatae, apice attenuatae;poris terminalibus, plerumque anticis, loculos diametro aequantibus, saepe primum poris terminalibus, dein rimis lateralibus, rariusporis terminalibus minutis sursum spectantibus, dehiscentes. -Sp. omnes inermes." Subsectio IV. Micranthes 1?. Anthoresis 2?. Anthopleuris ? 1. Oppositifolia * Indubitaria ** Lepidota *** Leiodendra ? 2. Pseudocapsicum ? 3. Bassovioides Sectio II. Leptostemonum "Antherae elongatae, apice attenuatae, poris terminalibus minutis retrorsisposticis vel sursum spectanibus. -Species nonnunquam inermes, plerumque aculatae."

phyletic groupsare identifiable,in partcorresponding to the traditionaldivisions in the genus, but some of the relationshipsrevealedby these techniquesare surprising. Based on analysesof moleculardatasets, Spooner et al. (1993) have shown that the tomatoes (formerly segregated as the genus Lycopersicon) are the sister group of the potatoes and should be considered as membersof Solanum subgenusPotatoe, Bohs (1995) has transferredall the species formerly segregatedas the genus Cyphomandra(Bohs, 1994) into Solanum, and it is clear that Seithe's (1962) chorus subgenerum Stellatipilumis polyphyletic. Since Dunal's monograph(1852), taxonomicwork in Solanumhas proceededat the sectional level and in regional floristic treatments.Recent sectional monographs in Solanum include the following: sect. Tuberarium(Dunal) Bitter(sects. Petota Dumort.and Basarthrum Bitter, pro parte, Correll, 1962); sect. Brevantherum Seithe (Roe, 1967b, 1972); sect. Acanthophora Dunal (Nee, 1979); sect. Androceras (Nutt.)Marzell(Whalen,1978, 1979);sect.Lasiocarpa D'Arcy (Whalen et al., 1981); the S. nitidumspecies group(sect.Holophyllaproparte)(Knapp,1989);sects. Lepidotum(Dunal)SeitheandCernuumCarv.(Carvalho & Shepherd, 1991; Carvalho, 1996); sect. Allophylla (Child) Bohs (Bohs, 1990); sect. Pachyphylla Dunal (as Cyphomandra, Bohs, 1994; see above); sect. Pteroidea Dunal (Knapp& Helgason, 1997); andcontinuingwork on various subgroupsof the complicated sect. Solanum L. (Maurella Dunal: Edmonds, 1972,

1977, 1978; Heiser, 1955, 1963; Heiser et al.. 1979; Henderson,1974; Schilling, 1981; Schilling & Heiser, 1976, 1979; Edmonds& Chweya, 1997). A list of regional floras treatingSolanim in some detail is provided in TableIII.

NOMENCLATURAL AND TAXONOMIC HISTORY OF SECTION GEMINATA Solanum section Geminatahad long been known as sect. Leiodendra Dunal, but the former name has priority under the rules of the InternationalCode of Botanical Nomenclature (Greuter et al., 1994; see Knapp,1983, 1984). The variousnamesthathave been appliedto the groupsof species includingthe lectotype (D'Arcy, 1972: S. nudum Dunal) of sect. Geminata are listed in the TaxonomicTreatment. Two species of sect. Geminataas treatedherewere known to Linnaeus(1753): SolanumdiphyllutmL., an ornamentalshrubprobablyfirstbroughtto Europefrom Mexico in the early seventeenth century (see discussion underS. diphyllum),and S. pseudocapsicum L., whichLinnaeusknewfromplantscollectedon Madeira, but almost certainlybroughtthereby early Portuguese traders(see Press & Short, 1994). In his 1813 thesis on the naturalhistory,taxonomy,and medical uses of Solanum,DunalincludedS. diphyllumandeleven other species in his group "c. Foliis ovatis, oblongis aut lanceolatis,glabrisautpubescentis."In a footnoteto the

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Table II Subgenericclassification of Solanum (according to D'Arcy 1972, 1991, and Nee, 1999). Characters defining the subgenera Inflorescence intra-axillary (leaf-opposed or terminal or various); anthers oblong; plants never armed; hairs simple, dendritic, or stellate Inflorescence axillary or intraaxillary in bi- or tri-furcation of stem; plants never armed; anthers oblong or tapered; hairs simple or dendritic

Characters defining the subgenera Stout anthers; simple hairs; no spines

Nee, 1999

Subgenus Bassovia

Stout anthers; simple hairs; pinnate leaves; axillary inflorescences; pointed fruits

Subgenus Bassovia

Subgenus Brevantherum (as subgenus Minon in D'Arcy, 1991) SubgenusPotatoe

Stout anthers;entire leaves; dendriticor stellate hairs

Included in subg. Solanum

Scandentspecies;pinnate leaves with interstitialleaflets; lateralpendulousinflorescences;articulatedpedicels Stout anthers; aneuploid chromosome numbers; Australia Stout anthers; South Africa


D'Arcy 1972, 1991 Subgenus Solanum

Subgenus Archaeosolanum Subgenus Lyciosolanum Subgenus Leptostemonum

Tapering anthers; stellate hairs, often with spines

Subgenus Solanum


Not treated Subgenus Leptostemonum

Inflorescence intra-axillary: anthers tapering; plants armed; hairs stellate, never dendritic

descriptive section of the thesis he commented, "S. raceme insteadof a cyme, see Morphology).Solanum acuminatum,gnaphalioides, fetidum diphyllum, ob- pseudocapsicum,by virtueof its possessionofangulateThismar- repandleaves, was placed by Dunal in a groupnamed longum;an sectionemnaturalemconstituunt?" ginal commentis the firstindicationof the naturalunity "Pseudo-Capsica" which also had as members S. of the group. Also included with S. diphyllumin this scabrum and S. aethiopicum, both spiny solanums. group were the following species which are still con- Otherspecies I have included in sect. Geminatawere sideredpartof sect. Geminatas.l: S. triste,S. oppositi- placed by Dunal(1816) in a groupcharacterizedby its folium(as S. urceolatum),S. acuminatum,S. oblongum, terminalinflorescences(S. sessile, S. oblongifolium,S. was assigned anonaefolium(= S. nudum))which was composed of andS.foetidum.Solanumpseudocapsicum to a hodgepodge of a grouppossessing sinuate leaves species froma numberof currentlyrecognizedsections. G. Don (1837) andWalpers(1844), followingDon's which also includedS. dulcamaraand several species of spiny solanums (Dunal, 1813). By 1816 Dunal had system almost exactly, named the group containing assigned these species and several others to a group SolanumdiphyllumandS. nudumas Geminata(Don at (butgrad.ambig.,see Knapp,1983)named"Leiodendra," the subsectionalrankandWalpersat the sectionalrank) it fromtherestofSolanumby,"Leaves possessingthe followingcharacters:"Arboress. frutices anddifferentiated and sometimes solitaryon the same raro in axillis foliis twin, entire, quite glabri, saepe geminis glabris, nervorumsubtuspilosis; racemissimplicibussymosis branch,rarelyaggregate.Calyx5-parted.Stamensequal." aut cymoso-umbellatis oppositifoliis; corollis sub-5- (G. Don, 1837:418). The speciesincludedin Don's sect. partitis."The charactersthathe consideredimportant Geminataare quite diverse;many are spiny solanums in the delimitationof the groupareclearlythe glabrous and the group as a whole is not as naturalas Dunal's natureof the plants and the leaf-opposed, simple in- muchsmallergroup"Leiodendra"(1816). NeitherDon florescence (which was misinterpretedby Dunal as a norWalperswas anexpertin Solanumorthe Solanaceae,

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HISTORYOF SECTIONGEMINATA Table III Regional floras with complete treatmentsof Solanum. COUNTRYOR REGION

AUTHOR

Brazil Costa Rica Venezuela Peru Panama Guatemala Veracruz, Mexico

Sendtner, 1846 Morton & Standley, 1938 Pittier et al., 1947 (list) Macbride, 1964 D'Arcy, 1974 [1973] Gentry & Standley, 1974 Nee, 1993

as was Dunal, so this is perhapsnot surprising. Sendtner,in his treatmentof Solanumfor Martius' Flora Brasiliensis (1846), for the most partfollowed Dunal's(1816) groupings,butconfinedhisLeiodendra Dunal to glabrous shrubs with geminate leaves and "pseudo-lateral"inflorescences.His treatmentof these species is excellent. He not only describesin detailthe Brazilianspecies, but many species fromPeruandthe Caribbeanas well. All of the species that Sendtnerincluded in his group Leiodendra are here retained as members of sect. Geminata. In his lastandmost extensivetreatmentofSolanum, Dunal(1852) definedhis groupLeiodendravery much as had Sendtner(1846). He includedLeiodendraas a subgroup of his larger group Oppositifolia (grad. ambig.),andcharacterizedit in the sameway as in 1816, "Arbores,fruticessuffruticesque;foliis saepe geminis glabris,raroin axillis nervorumsubtuspilosis; racemis simplicibus,cymosis autcymoso-umbellatis,oppositiHabitrange foliis; corollis albis subquinquepartitus." was extendedto subshrubs,andflowerswere described as white; otherwisethis descriptionis exactly the same as the one in theSolanorumSynopsis(1816), although manymore species were included(12 in 1816 vs. 37 in 1852). Dunal (1852) clearly distinguishedthose taxa with tomentoseleaf undersides(Indubitaria)andthose species with lepidote scales ("leproso-squamulosa," Lepidota) from his groupLeiodendra(see Table I for detailsof Dunal's 1852 classification).Delimitationof the groupnow known as sect. Geminatahas remained very similarto thatproposedby Dunal,but opinionsas to the relationshipsof the groupwith othersections of Solanumhave differedgreatly.Taxaincludedin Dunal's Oppositifolia but excluded from sect. Geminata as treatedhere are detailedin Excluded Species. Dunal (1852) considered those taxa with leaf-opposed inflorescences to be most closely related. He groupedLeiodendra,Indubitaria,andLepidotatogether in the largergroup Oppositifolia (see Table I). Seithe (1962, 1979), workingwith trichomemorphology,con-

cluded that the fundamentaldivision in Solanumwas taxaandthenon-stellatethatbetweenthe stellate-haired hairedtaxa.In herclassificationthe species inLepidota, possessing lepidotescales andstellatetrichomes,were placedwith otherstellate-hairedgroups.The othertwo groups from Dunal's Oppositifoliawere still consideredto be closelyrelated.SectionOppositifolium (Dlual) Seitheconsistedof threesubsections:1) Oppositifolium (Dunal)Seithe (largelyDunal'sLeiodendra),2) Silicosolanum(consistingof a singlespecies,S. trachytrichium Bitter,with unusualtrichomemorphology),and3)Indubitaria(those species with branchedtrichomes).She specified at least some of the species to be includedin each subsection,but in many cases the characterof trichomebranchingdoes notworkwhenmorethana single specimen per species is examined (see Morphology). Danert(1970, 1975),thoughconcentratingon inflorescence and sympodial structure,basically followed Seithe's (1962) system, with minor changes, none of which affect the placementof sect. Geminata.D'Arcy (1972) divided Solanum into seven subgenera (see TableII),clearlydifferentiating the simpleandbranched hairedgroupsas belongingto distinctphylogeneticlineages. His reasonsfor this arenot explicit, but fromhis conspectus,the intentis clear.In D'Arcy's (1972) system, sect. Geminata(as LeiodendraDunal)is placedin subgenusSolanum,while Indubitariais a subsection of sect.Holophylla(G. Don) Walp.in subgenusBrevantherum.Section PseudocapsicumBitteris includedas a subgroupof Indubitariain both D'Arcy's (1972) and Nee's (1999) systems. Hypothesesaboutrelationships between sections arenot presentedin D'Arcy's (1972) treatment,but from his placement of sect. Geminata, its relationshipsappearto be with sect. SolanumL. To date only three species of sect. Geminata as treatedhere have been used in molecular systematic analyses: Solanum pseudocapsicum, S. arboreum (Bohs & Olmstead, 1997; S. pseudocapsicum only in Bohs & Olmstead, 1999), and S. aphyodendron (Olmstead & Palmer, 1997). In analyses using ndhF

8

sequences (Bohs & Olmstead, 1997) and cpDNA restriction site variation (Olmstead & Palmer, 1997), a sister group relationship for S. pseudocapsicum and either S. arboreumor S. aphyodendronwas strongly supported. It is clear that past segregation of the branched-trichome taxa (cf. Dunal, 1852; D'Arcy, 1972) is not justified. All three of these taxa of sect. Geminatahave not been used in a single analysis, so molecularrelationshipswithin the groupremainto be resolved.It is also clearthatmorerobustsamplingwill greatlyimprovephylogeneticinference(see Perssonet al., 1994; Knapp et al., 1997; Chase et al., in press). However, on-going studies (Bohs, pers. comm.) indicate that members of sect. Holophylla s.str. (i.e., S. Bitter& Lillo, see Excluded Species for a argentinurm complete list) may also be partof the clade containing membersof sect. Geminata. My morphologicalworkwith sect.Geminataclearly showed that trichome morphology and inflorescence structurewere both extremely variableattributes(see discussions of these charactersin Morphology).Variation occurswithin species, populations- andeven individualsin the degreeof trichomebranching,which traditionallyhas been one of the most importantcharacters used in Solanumtaxonomy. Section Geminata as delimitedhereincludesspecieswithsimpletrichomes and species with branched trichomes, a conclusion strongly supportedby recent molecular analyses (see above).Insteadof delimitingformalsubsectionalorother groupings at this point, I have brokensect. Geminata s.i., which is largeandunwieldy,into a set ofputatively monophyleticspecies groups.The monophylyof these smaller groups can be tested (see Knapp, 1991b), and fromthis a stableandtestableclassificationconstructed. In this monographI have treatedthe section in its broadestsense and have assembled groups of species I hypothesize to be monophyletic.This has meantthat I have includedtaxapreviouslyconsideredto be members of various other sections of non-spiny solanums: most notably Pseudocapsicum, Holophylla, and Indubitaria. This to a certain extent means that sect. Geminiatas.l. is probably not a monophyletic group, while its component species groups almost certainly are. The section as treated here is most probably a paraphyleticgradewhose relationshipsto otherclearly monophyletic groups of solanums are not at all resolved. Species groups that I think will be partof the wider set of monophyletic groups related to the taxa treated in this monographare sect. Holophylla s.str. (species list in Excluded Taxa), sect. Pachyphylla (Bohs, 1994), sect. Cyphomandropsis(Bohs, 1994), sect.Allophylla(Bohs, 1990),theSolanumthelopodium species group (Knapp, 2000), and possibly the S.

FLORA NEOTROPICA

nitidumspecies group(Knapp,1989). SectionsLepidotum,Cernuum,andExtensumarealso possibly related to these groups,althoughthis has not been traditionally considered due to their possession of lepidote scales, chaffy hairs derived from lepidote scales, and stellate hairsrespectively.Generalarchitecture andinflorescence morphology is very similar however in all of these groups. A brief key distinguishing these groups and differentiatingthem fromsect. Geminatas.l. as treated here is providedin the TaxonomicTreatment,andspecies lists areprovidedeitherin the referencescited, in the Appendices, or in Excluded Species.

MORPHOLOGY HABIT Speciesof sectionGeminataareunusualin Solanum in being plants of primaryforest understory,whereas the genus as a whole is mainly one of open, disturbed areasandlightgaps. Speciesof the sectionrangein habit fromsmallshrubsto trees 10-15 m talland20 cm diameter,butarealwayswoody. Some species alwayshave a well-definedtrunk(e.g.,S. acuminatum, S. trichonelron), while othersaremany-branchedfromthe base. Variation in habit is common within species and is often correlatedwith habitat. STEMS The young erect stem is monopodialwith alternate leaves arrangedin a 2/5 phyllotaxic spiral. When the reproductivephasebegins, stem growthbecomes sympodial(see Danert,1958, 1967, 1970;Child,1979;Child & Lester, 1991; Bell & Dines, 1995, for diagramsand explanations of terminology concerning sympodial branchingin Solanum).Eachinflorescenceis developmentally terminal,and stem growthproceeds from an axillarylateralshoot. This shoot is againterminatedby an inflorescence, the stem continuationis initiated in the axil of the leaf subtendingthe inflorescence,andso on (Danert,1967). Thusall membersof the Solanaceae are sympodialwith determinatemodules (Bell, 1991; Bell & Dines, 1995). The numberof leaves in a sympodialunitandtheirarrangementareimportantcharacters in sect. Geminata.Sympodiain sect. Geminataare either1) plurifoliate,2) difoliate,3) difoliate-geminate, 4) unifoliate,or 5) "fasciculate"(Danert,1967)(see Fig. 1 for diagramsof these sympodial types). Plurifoliate sympodial units are considered to be primitive in Solanumby Danert(1967, 1970)andChild(1979),while the othertypes arespecializationswithinthe genus.The plurifoliatespecies in sect. Geminataareprobablysecondarily so; many of the species possessing this con-

MORPHOLOGY

9

B

E

F

C

D

G H

FIc. 1. Sympodial types found in section Geminiata. The colors (black & white) represent different shoot generations. Patterns of concaulescence can be easily seen. Diagrams modified from Danert (1967). A. plurifoliate sympodial units. B. trifoliate sympodial units. C. difoliate sympodial units. D. difoliate sympodial units with geminate leaves, inflorescence internodal. E. difoliate sympodial units with geminate leaves, inflorescence leaf-opposed. F. difoliate sympodial units with geminate leaves, leaf pair markedly anisophyllous, inflorescence leafopposed. G. unifoliate sympodial units, inflorescence leaf-opposed. H. fasciculate sympodial units, inflorescence overtopping the new shoot.

dition are shrubsof river beds subject to periodic inundation,andarespecializedin otherfeatures.Thegeminateconditionso common in sect. Geminata(Fig. 1E) is caused by suppressionof growth in various partsof the stem axis, andthe two leaves of a geminate cluster are from differentshoot generations. Architecturalmodels have been applied to various

genera in the Solanaceae (Bohs, 1994; Bell & Dines, 1995), andbranchingpatternsarecommonly very precise andpredictableat the species level. In the original architecturalscheme of Halle et al. (1978) membersof the Solanaceaecan be classified in bothmonoaxialand polyaxialmodels,with threedifferenttypes ofpolyaxial models being present (Bell & Dines, 1995). Models

10

representedin the genus Solanum are Prevost's (species of Cyphomandra,see Bohs, 1994;Solanummorii, see below), Leeuwenberg's (sects. Brevantherum, (sect. Allophyllum,Holophyllaproparte),Chamberlain's Pteroidea), and Mangenot's (sect. Solanum) (Bell & Dines, 1995). Membersof sect. Geminataseem to most with closely ressembleeitherthe modelof Chamberlain, monchasialbranchinganda sympodialtrunk,or the intermediateandmixed model describedby Bell & Dines (1995) from Lycianthes sanctae-clarae (Greenm.) D'Arcy. This mixed model involves a primarymodule terminatedby a flower and one dichasial branch,this producingtwo indefinite monochasia. The bud in the axil of the final leaf also producesa monochasium,resultingin a tierofplagiotropicbranches(Bell & Dines, 1995). Members of all the species groups in sect. Geminatahave architecturesimilarto thatof some species of Lycianthes, but detailed studies remain to be carriedout. Species in the S. confine and S. dolosum species groups conform more to the model of Chamberlain, but with the addition of tiers of plagiotropic branchesas describedforLycianthes.Specimenlabels on sheets in MPU indicate that S. leucocarpon conforms to Troll'smodel (Halle 2199) with long, plagiotropic branches,or to Pr6vost'smodel (Prevost 177). Sheets of S. oppositifolium(Halle 2241) statethatthe plants conform to Troll's model and those of S. morii (Prevost 1613, Halle 2377) to Prevost'smodel. These collections date from the 1970s and undoubtedlyrepresent field assessments, but it is clear thatmore work needs to be done with members of this group. Architecturemay provide useful charactersfor the recognition of monophyletic groups within sect. Geminata. The sympodialgrowthpatternof reproductivestems often gives them a zigzag appearance,particularlyin the Solanum confine and S. dolosum species groups. Branchorientationvariesbetween species and species groups,but is difficult to assess fromherbariummaterial. Forthose species I have seen in the field, this characteris discussedin the species descriptions.Branches are generally held upright,or at an approximately45? angle. In the S. confine andS. dolosum species groups however, the branchesare held parallelto the ground, giving the shrubsa pagoda-likeaspect.This may be an advantagefor light gatheringin the darkforest understory,the common habitatfor these species. The barkof these woody plants is quite variablein color and textureon younger stems, rangingfrom reddishandexfoliatinginSolanumtuerckheimii, grayishand smoothinS. arboreum,to brightgreenandstronglywinged in S. chlamydogynum andS. oetens. Inthosespeciesthat attainlarge diameters(15-20 cm dbh), the barkof the older stems and trunksis usually smooth and grayish-

FLORA NEOTROPICA

however,herbariumlabels tinged.InS. chlamydogynum mentionthatwings on the stems arepersistenton stems up to 10 cm in diameter.Woodof species attainingsuch diametersandheights has a distinctsmell of rawpotatoes when cut and is quite soft. Detailed descriptions of the wood anatomyof threespecies of sect. Genminata (S. oblongifolium,S. trichoneuron,andS. triste)areprovided by Carlquist(1992). Solanumoblongifoliumhas no growthrings in the wood, perhapsdue to habitator relativelycontinuousgrowth(Carlquist,1992). Rhomboidal crystals and crystal sand occur in the wood of both S. triste andS. trichoneuron(Carlquist,1992). LEAVES Leaves in section Geminataare simple andusually entire,and at first glance appearquite uniformamong species.Amongthe leaf charactersusefulin distinguishing between species are leaf size, leaf shape, margin characteristics,venation, vestiture,and apex andbase shape. If present,trichomesareusually denseror only found on the undersurface.The trichomedistribution patternis an extremely useful characterfor some species, but in otherspecies can be extremelyvariableand of little use taxonomically.In general,membersof the Solanumsessile and S. oblongifoliumspecies groups have the largest leaves, while membersof the S. colnfine species group have the smallest leaves. Several species (S. monadelphum,S. amnicola,andS. imberbe) havenarrowlylinearleaves.Thesespeciesgrowin stream beds andaresubjectto periodicseverewaterloggingand swift currents.Theirpeculiarleaf shape(forSolanum) maybe an adaptationto theirextremehabitatandis typical for rheophytes(van Steenis, 1981). As in therestofthe family,isolatedidioblastsof"crystal sand" (tiny calcium oxalate crystals) occur in the parenchymalayerof the leaflaminae(Solereder,1908; Carlquist,1992).Thesize andnumberof theseidioblasts appearto differ between species, but furtheranatomical work is neededbefore conclusions can be drawnas to theirusefulness as differentiatingcharacters. INFLORESCENCES Inflorescences of section Geminataare variously modified helicoid cymes. They are usually bore opposite a geminateleaf cluster,or single leaf in the case of those species with unifoliate sympodia.They occasionallyappearto be intemodalor extra-axillary,due to adnationof the stem and inflorescence axes (Danert, 1967). This characteristicoften varieswithina species, and even within an individual plant. In the Solanum sessile andS. oblongifoliumspeciesgroups,lateralshoot growthoften lags behindinflorescence expansionand development, causing the inflorescence to appear

11

MORPHOLOGY

branch-terminal.The branch-terminalinflorescence occurs in sect. Holophylla (G. Don) Walp.and in sect. BrevantherumSeithe, but in these groups no further branchelongation occurs (see Knapp, 1989), and the inflorescenceterminatesa shoot. This superficialsimilarityhowever,has resultedin severalof the species of the S. sessile complex being previously placed in sect. Holophylla.The degree to which the lateralshoot lags behindtheinflorescenceis variable,bothbetweenplants in a populationandbetweenbrancheson an individual. Branchescollected in different stages thus appearto have completely differenttypes of inflorescences and often were classified as different species in different parts of the genus (see discussion of S. sessile and Knapp, 1991b). See Fig. 1 for diagrams of inflorescence positions commonly found in sect. Geminata. The inflorescence in species of sect. Geminata is simpleto manytimes branched,stoutto threadlike,and with few to many flowers. The arrangementof flowers on the inflorescencecan be deducedfromthe scars left by the flowerandfruitpedicels when they fall. This is a useful characterand has been largely overlooked (but see D'Arcy, 1973).Pedicelscarsareclosely spaced(oftenoverlapping)in some speciesgroups,andwidely and irregularlyspacedin others.The scarsareflushwith the inflorescence axis,notleavingsmallplatforms(see Knapp, 1989), pegs (see Bohs, 1994), or sleeves (see Knapp, 1989) as in otherpossible relatedgroups (see above). In general inflorescences are simple, but in the Solanum sessile and S. oblongifoliumspecies groups and in some species of the S. amblophyllumspecies grouptheyaremanytimesbranchedandoftenverylarge. Diagramsof the differenttypes of inflorescencesoccurringin sect. Geminataarepresentedin Fig. 2.

A

^ B

C FIG. 2. Inflorescencetypes in section Geminata.A. stout with closely spaced pedicel scars. B. filiform with widely and unevenly spaced pedicel scars. C. branched.

lobes) have distinctive and peculiar calyx lobe morphol-

ogy; these variations are discussed in the individual species treatments. Species of section Geminata have amongst them some of the smallest flowers in Solanum.Averagecorolla diameteris about 8 mm, but some species have corollas as small as 4 mm in diameter.The corolla is usually white or greenish-white, but occasionally the FLOWERS edges of the lobes are tinged purple, particularilyin As in most othersolanums,flowers of sect. Gemin- plants growing in full sun. The corolla is deeply lobed ata arepentamerous,actinomorphic,andgamopetalous. and stelliformto shallowly lobed andmorepentagonal Floweringpedicelsareusuallydeflexed andquiteslen- in outline. The lobes are usually rathernarrowand ofder.Constrictionsat the base of the calyx tube are use- ten the corollatube is minute.A few species have shalful charactersin severalspecies andspecies groups.The lowly lobed corollas with a broadlyopen corolla tube, calyx is 5-parted,with variously developed deltate to and the flowers are thus more pentagonal in outline. lanceolatelobes. In some species the lobes are minute, The degreeto which corollalobes arereflexedat anthemereprojectionsfromthe rim of the calyx tube, while sis is an importantcharacter.This characteris easily in others,such as Solanumtanysepalum,S. irregulare, seen in live plants, but with more difficulty in pressed andmembersof theS. pseudocapsicumspecies group, specimens.Onlya few species(Solanumtrachytrichium, the calyx lobes are long-triangularand occasionally S. campaniforme,andS. validinervium)have campanualmost equal to the corolla lobes in length. The calyx latecorollas;these arealso those species with shallowly lobesarenotusuallyreflexed,butreflexedcorollalobes lobed, pentagonalcorollas. In many species the lobes at anthesisare characteristicof several species. A few are held planar (i.e., perpendicularto the pedicel or species (notablyS. abitaguense with its closed calyx spreading) at anthesis, while in others the lobes are envelope, S. platycypellumwith its flattened, almost slightly reflexed. The orientationof the corolla lobes lobeless calyx, andS. pastillum with its globose calyx does not generallychange over the reproductivelife of

FLORA NEOTROPICA

12

A

B

D

C

FIG. 3. Corolla types in section Geminata. A. campanulate. B. lobes planar. C. lobes strongly reflexed. D. with unequal anthers.

a flower, which is usually five days to a week. Many membersof the S. nudumspecies groupare characterizedby theirslightlyreflexedcorollalobes. Specieswith stronglyreflexedcorollalobesarefoundin theS. confine, S. arboreum,andS. unifoliatumspecies groups.In species with this flower type the lobes are held parallelto the pedicel, and only begin to close aroundthe anthers when flower wilting begins. Interestingly,these arethe smallestflowersin the section.The stronglyreflexedcorollalobes may be a strongsignalto pollinatorsin these otherwise inconspicuous flowers. See Fig. 3 for diagramsof the majorcorollatypes in sect. Geminata. The anthers of species of section Geminata are small, oblong, and strongly to weakly connivent. The anthersare usually brightor pale yellow, but those of SolanumleucocarponandS.pseudocapsicumarebright orange-yellow.The color is not the color of the pollen, butof the antherwalls, andmay serve to attractpollinators.Theanthersof some membersoftheS. leucocarpon species group (notably S. leucocarpon) are strongly conniventandsuperficiallysimilarto theanthersof some species of sect. Pachyphylla(the genus Cyphomandra, see Bohs, 1994). They lack, however, the strongly developed antherconnective of that section. As in all species of Solanum,the anthersareporicidalat the tips. In sect. Geminata,however,as the anthersdrythe pores split open towardthe base of the antherandlengthento slits (see Bonner& Dickinson, 1989, for a detailedanatomicaldescriptionof a similarsituationinLycopersicon esculentumMill. [SolanumlycopersicumL.]). At dehiscence, the brightwhite lines along the lines of opening indicatetheprescenceof calciumoxalate,whichhas been implicatedin the dehiscence process itself and is commonin the Solanaceae(Bonner& Dickinson,1989, 1990; D'Arcy et al., 1996). The filaments are much shorterthanthe anthers,areinsertedin the corollathroat, andarebasallyconnate.Unequalanthersizes arefound

in two species, S. pseudoquina and S. reitzii. In these species, two of the anthersandtheirfilamentsare long, and the otherthree are short (Fig. 3D). The anthersin thesetwo species areless tightlyconniventthanthose in otherspecies, arecurvedin longitudinalsection,andthe pores do not split open with age or upon drying. Pollen grainsof section Geminataspecies, as in all other species of Solanum, are tricolporate,pouting at the equator,and have a minutely granularexine (see Anderson & Gensel, 1976; Punt & Monna-Brands, 1980; Edmonds, 1984; Bohs, 1994). Pollen grains of membersof sect. Geminataare on the orderof 12 gm in diameter.No notabledifferencesin pollensize ormorphology have been found between species or species groups in sect. Geminata(see Fig. 4). The ovaries in most species of sect. Geminataare glabrous, but some members of the Solanum sessile, S. nigricans, S. arenarium, and S. nutans species groupshave denselypubescentovariesandstyle bases. The trichomes are persistent on the maturefruit; furtherdetails are discussed with otherfruitcharacters. FRUITS Fully developed ovaries of species of section Geminataare globose or depressed-ovoidandusually glabrous.Occasionallythe fruitsaresomewhatpointed at the apex (e.g., Solanum nigricans, S. stipulatum). The fruitis a bicarpellate,usually bilocularberrywith axile placentation.They are usually few-seeded (1050 seeds), an unusual condition in Solanum. In some groups, particularlythose with flattened seeds (see below), berriesaremore typical forSolanumandmay contain 100-200 seeds. Berries are usually green or yellowish-green,andrelativelyhardat maturity.Many species have fruitwhich becomes softer and yellowgreenvery rapidly(overnight,or in a single day). These fruits are taken by bats or birds almost immediately

13

MORPHOLOGY

_______20_gm FIG. 4. Pollen grains in Solanum section Geminata. All polar views. A. S. arboreum, Costa Rica (Bohs 3010). B. S. rovirosanum, Costa Rica (Khan et al. 1319). C. S. incomptum,Costa Rica, (Tonduz13666). D. S. leucocarpon, FrenchGuiana (Sagot 454). E. S. leptopodum,Colombia (Philipson et al. 2184). F. S. nudum,Belize (Whitefoord9065).

14

FLORA NEOTROPICA

- ::;1: 1

A ...

''-4iy

;

..

0**

..

FIG. 5. Fruiting pedicel types in section Geminata. A. erect (Solanum arboreum). B. slightly deflexed (S. nudum). C. strongly deflexed and expanded at the apex (S. tenuiflagellatum).

(Knapp,1986a;Dinerstein,pers.comm.).The fruitflesh is usually green or pale greenish-white and hard,becoming waterywhen the fruitripens.Even in ripe fruit the flesh is not sweet. Members of the Solanum pseudocapsicum species groupandS. spirale of the S. nudumspecies grouphave more typically solanaceous brightorange or red-colored, soft, juicy fruits. The majorityof species in sect. Geminatahave glabrous fruit, but those taxa with pubescent berries fall intotwo generalcategories.Firstarethose species with simple uniseriateor dendritictrichomeson the mature berries.Solanumgnaphalocarpum,S. oblongum,and some members of the S. sessile, S. nigricans, and S. nutansspecies groupshave this type of pubescentfruit. The trichomespersistthroughovary developmentand are presenton the matureberry.The trichomes on the maturefruit are usually similar to those found on the restof theplant.Importantdifferencesaredetailedin the species accounts. The berry of S. gnaphalocarpon is extremein this regardandis denselycoveredwith elongate, echinoidtrichomessuch thatthe pericarpis never visible. Solanumabitaguense,S. cucullatum,andsome membersof the S. arboreumspecies group also have pubescent berries, but of a completely different and probablyindependentlyderivedtype. In these species, the ovary is glabrous at anthesis, but during fruit de-

velopmentacquiresa coatingof grayishorpinkishpapillate trichomes.Thesepersiston the maturefruit,butare inconspicuousunless viewed at high magnification. The orientationanddegreeof elongationand/orexpansion of pedicels in fruitare importantcharactersin sect. Geminata.The pedicels elongatesomewhatin the Solanum nudumspecies group, but are not markedly differentin shapeor orientationfromtheirconditionat anthesis.Severalgroupsof species (S.pseudocapsicum, S. arboreum,some speciesoftheS. nudumandS. sessile species groups)arecharacterizedby erect,woody, fruiting pedicels. These pedicels are not much elongated, but aregreatlyexpandedin diameterandat fruitmaturityarethickandwoody alongtheirentirelength.Fruits in these species areheld above the leaves. Anotherextreme is seen in those species with elongate pedicels and pendantfruits (S. confine and S. dolosum species groups).Here the fruitingpedicel is two to threetimes as long as the floweringpedicel andis usuallyexpanded andrathercorkyjust below the calyx tube. The berries of these species hang below the leaves. The effective pedicel length is often increased even furtherby the elongate inflorescence, which in some species can be up to 20 cm long (S. tenuiflagellatum and S. leptorhachis). Generalized fruitingpedicel types are shown in Fig. 5.

15

MORPHOLOGY Table IV Seed type distribution in the species groups of section Geminata. FLATTENED-RENIFORM

SEEDS

Solanum oblongifolium species group Solanum pseudocapsicum species group Solanum nudum species group Solanum leucocarpon species group Solanum nutans species group Solanum amblophyllum species group

SEEDS Seeds of Solanumspecies areusuallyflattened,reniform,andhavesomewhatincrassate(thickened)margins. In sect. Geminata,six species groupshave this type of seed (hereafterreferredto as flattened-reniformseeds, see Table IV). Flattened-reniformseeds are usually small, 1-2 mm in length,yellow or darkbrownin color, and the surfaces are minutely pitted (Fig. 6A). The incrassatemargin is paler than the body of the seed. The remainderof species groups in the section (the majority,see TableIV) have large,roundedseeds with very thin seed coats, throughwhich the spiralembryo characteristicof Solanumcan be clearly seen (hereafterreferredto as ovoid-reniformseeds).Ovoid-reniform seeds are larger,usually 2-4 mm in length, pale tan or brightgreenin color,andaregenerallyfew in any given fruit (Fig. 6B,C). They dry out easily due to the thin seed coat, and are difficult to germinateafterdesiccation. These seeds are unusualin the genus. Two of the few othersectionsin whichtheyoccuraresect.Pteroidea Dunal(Knapp& Helgason,1997)andtheS.thelopodium species group (Knapp,2000), but in those groups the seed coat is not thin and the testa walls are thickened (see below). The generalappearanceof the ovoid-reniform seeds in sect. Geminatais so aberrantthat they have been misinterpretedas not belonging to Solanum at all. For instance, Bitter, in a note on the holotype of S. tenuiflagellatum, commented that the fruit in the packet probably did not belong to the specimen and probablywas not even a Solanum(see discussion of S. tenuiflagellatumfor text of his comment). The seeds of S. tenuifagellatunm aretypicalof the ovoid-reniform type found in sect. Geminata. Removalof the outerseed coatwall revealspatterns of lateralcell wall thickeningthatdiffer between taxa (Soueges, 1907; Edmonds, 1983; Lester & Durrands, 1984; Knapp& Helgason, 1997; Whalen & Caruso,

OVOID-RENIFORM

SEEDS

Solanum deflexiforum species group Solanum arboreum species group Solanum unifoliatum species group Solanum robustifrons species group Solanum narcoticosmum species group Solanum nigricans species group Solanum arenarium species group Solanum sessile species group Solanum confine species group Solanum dolosum species group

unpubl.).Throughoutthe familySolanaceaelateralseed coat walls arecomposed of thickenedpyramidalbases toppedby elongate,lignifiedprojections(Sou6ges,1907; Mohan& Singh,1968;Edmonds,1983;Hoare& Knapp, 1997). The projectionsareconnectedby thinner"membranous"sections of material(see Figs. 6D, 7A,C,D). Flattened-reniform seedsin sect.Geminata(see TableIV) conformto thispattern.Ovoid-reniformseeds,however, have a very differentlateralwall structure.Lateralcell walls in these seeds are thin, and do not possess elongate finger-like projections (see Knapp, 1991b; Fig. 7B). Seed shapeandfine structurearecorrelatedin sect. Geminata,andserveto dividethe sectionintotwo major groups: Groups I-VI have flattened-reniformseeds, GroupsVII-XVI have ovoid-reniformseeds. TRICHOMES Trichome morphology has been used extensively in Solanum taxonomy (Edmonds, 1982; Roe, 1971; Seithe, 1962, 1979;Seithe& Anderson,1982;Whalen, 1978, 1979;Whalenet al., 1981).Eightbasic hairclasses occurringin Solanumaccordingto Seithe(1962, 1979) arelisted in the left-handcolumn of TableV, using her terminology.Standardizedtermsaregenerallyused in discussions of more complex hair classes (i.e; stellate hairs), but the terminology available for simple and branchedtrichomes does not adequatelyreflect their structuraldiversity.Roe (1971), in his attemptto present a standardizednomenclatureforSolanumhairs,went a long way toward solving this problem. His terminology is presentedin the right-handcolumn of TableV. Seithe(1962, 1979) consideredsimpletrichomes("finger hairs" in her terminology) to be primitive in Solanum. She believed them to representa good case of Haeckel's law of ontogeny recapitulatingphylogeny (Haeckel, 1883). Glandular"finger hairs" occur on the cotyledons and seedling leaves of all of the spe-

FLORA NEOTROPICA

16

:w,~, ~

_O~CSE~ !;":_It.

""

FIG. 6. Seed types in section Geminata A. flattened-reniform seed 50x (Solanum acuminatum, Knapp et al. 6343). B. ovoid-reniform seed 30x (S. sessile, Knapp & Mallet 6442). C. ovoid-reniform seed 30x (S. abitaguense, Knapp & Mallet 6180). D. enzymatically digested flattened-reniform seed showing the lateral cell wall thickenings 50x (S. nudum, Nee et al. 30019).

FIG. 7. Lateral seed coat wall thickenings in section Geminata. A. from flattened-reniform seeds 500x (Solanum leucocarpon,

Knapp & Mallet

6284).

B. from ovoid-reniform

seeds

500x (S. sessile,

Knapp & Mallet

6442).

C. flattened-reniform seeds with rectangular or square cells lOOOx(S. nudum, Nee et al. 30019). D. flattenedreniform seeds with sinuate-walled seeds lOOOx(S. campaniforme, Steyermark et al 88179)

17

MORPHOLOGY Table V in Solanum to trichomes (for definitions of these terms the reader Terminology applied is referredto the original publications). SEITHE(1962,1979) finger hairs branchlet hairs stellate hairs gland-tipped finger hairs gland-tipped stellate hairs

ROE(1971) simple trichomes uniseriate multiseriate stellate trichomes porrect stellate peltate multangulate multiradiate echinoid

multicellular glands prickles

dendritictrichomes furcate dendritic

bristles some modified trichome types glandular dendritic-echinoid

cies studied by Seithe, and are the least structurally complex of all of the hairclasses. Two distinctphyletic lines or transformationseries were hypothesized by Seithe: 1) gland-tippedfinger (simple) hairsto stellate hairs, and 2) gland-tipped finger (simple) hairs to branchlet(branched)hairs. Section Geminatahadtraditionallybeen characterized as those species that are glabrous or possessing only simple trichomes (D'Arcy, 1973; Gentry & Standley,1974; Seithe, 1962). Subsectionlndubitaria (see NomenclaturalandTaxonomicHistory)was characterizedby the possession of only branchedtrichomes (Seithe, 1962). Seithe (1962) recognized the close relationship of these two groups based on habit, flower and fruit morphology, and inflorescence and sympodial structure, and placed them in a single section: Oppositifolium.D'Arcy (1972), however, placed the two groups in different subgenera.While examining specimens in the course of this study, I found that in this group these two hairtypes differ only by degree, and variationandpolymorphismexist at all taxonomic levels. One memberof a pairof closely relatedspecies may possess branchedtrichomes while the other has only simple trichomes(Solanumchlamydogynumand S. obovalifolium); different populations of a single species may vary in their possession of simple or branched trichomes (S. leucocarpon, S. lindenii, S. confertiseriatum,S.pseudocapsicum);individualsin a

populationmay vary in their possession of branched or simple trichomes(S. confertiseratum);andfinally,a single individual may have simple trichomes on one leaf and branched trichomes on another (S. confertiseriatum,S. pseudocapsicum).It is clearthen that the characterof simple versus branchedtrichomes is not as simple as was previously considered in sect. Geminata.SectionGeminataas delimitedhereincludes both simple andbranchedtrichomespecies. Three basic types of unbranchedtrichomes occur in sect. Geminata.The most widespreadis the simple uniseriatetrichome,consisting of a single row of cells (Figs. 8A, 9A). The basal cell or cells surroundingthe basal cell are occasionally somewhatmodified (Figs. 8C, 9B), but generally the cells of the hair are of approximatelyequal size and shape (save, of course, the tip, which is pointed).The cell walls areoftenquitethin, and, if so, the cells collapse when dry.In the Solanum sessile species group however, the cell walls of uniseriatehairsarerelativelystiff andretaintheirshape even on herbariumspecimens. Simple uniseriatetrichomes arefoundto some degreein all species groups. The second type of unbranchedtrichome,the papillate trichome, is characteristicof the S. arboreumand S. robustifronsspecies groupsbut is also found to varying degrees in most of the other groups. Papillatetrichomes are technically a subset of simple uniseriate trichomes,but are so differentin appearanceandtaxo-

FLORA NEOTROPICA

18

A

C

B

D

FIG. 8. Unbranched trichome types in section Geminata. A. simple uniseriate. B. papillate. C. uniserate with multiseriate base. D. unicellular. All drawn approximately 10x life size.

19

MORPHOLOGY

d_f _ f.~?:;?"?~c~;c~flF~,~t~l~''~~ Cll~q~-~?~g~S~i~i'f c~-. ' ..

...

FIG. 9. Scanning electron micrographs of unbranched trichome types in section Geminata. A. simple uniseriate trichomes from the pedicel of Solanum oblongum, 500x, (Knapp & Mallet 6343). B. papillate trichome from the new growth of S. arboreum, lOOOx,(BH 84:140). C. unicellular trichome with a broad multicellular base from S. trachytrichium, 480x, (Cabrera 69). D. uniseriate trichome with multiseriate base from the new growth of S. validinervium, 204x, (Knapp & Mallet 6782).

nomic distributionamong species that I preferto treat them as a separatehairtype. They are uniseriate,or in some cases uni-cellular,with thin, crumplingwalls in dry or preservedmaterial.The distal cell of the hair is rounded(Fig. 9B). The fine structureof papillate trichomes is difficult to assess with driedmaterial,as the trichomescollapse andthe numberof cells in each hair is nearlyimpossible to determine.Papillatetrichomes are usually found on the young leaves and stems, and on the inflorescences in those species where they occur.In dry specimens they are often reddish in color. The last and least common type ofunbranchedtrichome is the multiseriatehair,foundin only a few species, e.g., SolanumvacciniiflorumandS. validinervium

(Figs. 8C, 9D). Simple multiseriatetrichomes consist of severaladjacentrows of cells. The structureis similar to that of the simple uniseriate trichomes. In S. vacciniiflorum,simplemultiseriatetrichomesarefound on the upperportionsof the stems in conjunctionwith simple uniseriatetrichomes. Fourbasictypesof branchedtrichomesoccurin sect. Geminata:echinoid/dendritic-echinoid (Christmas-treelike),arachnoid,dendritic,andfurcate(Fig. 10).Themost complex structurallyare the echinoid and tree-liketrichomes. These types of hairs occur in some species of the Solanum nutans species group and S. gnaphalocarponof the S. arenariumspecies group.Thetrichome axis or stalk is either uniseriate or multiseriatebut is

FLORA NEOTROPICA

20

B

A

C

D

FIG. 10. Branchedtrichome types in section Gemninata (see text). A. echinoid. B. arachnoid.C. dendritic. D. furcate.

oftenobscuredby the numerousbranches.Therays(side branches)alwaysprojectat all anglesalongthe axis and are very closely packed and occasionally branched themselves (Fig. O1A).Two main types of echinoid trichomesoccur in sect. Geminata:1) short,sessile trichomes with numerous branchesobscuring the stalk aretermedechinoid;and2) elongate densely branched trichomes (Roe's dendritic-echinoid)are termedhere "Christmas-tree-like," following Seithe (1962, as see Knapp, 1989). "tannenbaumartig," Manyspecies previouslyconsideredto be members of subsectionIndubitaria(includingthe lectotypespecies SolanumbrachystachysDunal= S. nigricans)have arachnoidtrichomes(Fig. 10B). Arachnoidtrichomes

are complex multicellular hairs that appear felt-like when seen with the nakedeye or the dissecting microscope. The cells are usually quite small, thin walled, and the hair itself is an irregularlybranched,fragile structure.Arachnoidhairsaresimilarin appearanceand probably structurallyrelated to papillate trichomes. These trichomesare often deciduousand so areabsent from older leaves. Like papillate trichomes, they are densest and most commonly seen on the new growth and the inflorescences of the species in which they occur. As a leaf matures, it often loses its coating of arachnoidtrichomes (e.g., S. maturecalvans). The third and most common type of branchedtrichome is the dendritic trichome (Asthaare of Seithe,

21

MORPHOLOGY

for leaf

underside

of

. nudum

500x

(from

seed

of Nee

et al. 30019,

BH

84:177).

C. glandular

trichomes

along

a vein on the abaxial leaf surface of S. oblongum, 500x, (Knapp & Mallet 6343). D. glandular trichome of S. Mallet 6343). 2000x, (Knapp oblongum, 6343). (Knapp & Mallet oblongum, 2000x,

1962), consistingof a uniseriatemain stem with few to several divergent branches seemingly distributedat random(Figs. 10C, 11B). The numberand length of the branchesvaries considerably,but any given branch is usually only one or two cells long. The branchesare not as densely packed as those of the echinoid or treelike trichomesandthe stalkis always visible. Dendritic hairsare found in several species groupsand are often foundin conjunctionwith simple, uniseriatetrichomes (see also Knapp, 199 la). The fourthtrichometype occurringin theseSolanum species is the furcate hair, technically a type of dendritichair.Furcatetrichomesarehairsthatare divided into two branches(Figs. 10D, 11A). Usually one cell is branched,and appearsbud-like. Roe (1971) com-

mentsthat"truefurcatehairsareprobablynot common in Solanum."They arevery commonin sect. Geminata. These small trichomes often appear simple and uniseriateunderthe dissecting microscope, but when viewed at high magnificationstheirstructurebecomes clear (Fig. 11A). The style base and fruittrichomesof many of the species of the S. sessile species groupare of this type. All of the largertrichome types in sect. Geminata are non-glandular.On mature foliage glandular trichomes occuron the veins andnew growthbutthe hairs themselves are always tiny (Fig. 11C,D). I have found at least some of these minute, glandulartrichomes on almost all the species of sect. Geminata. The distribution of trichomes on the plant, their

FLORA NEOTROPICA

22

color in driedmaterial,andtheir structureare all good charactersfor identificationat the species level, especially when used in conjunctionwith floral and inflorescence characters.Some species groups are characterizedby the presenceof a particulartrichometype or types:thick-walled,golden,simpleuniseriateor furcate trichomes in the Solanum sessile species group (see Knapp,1991a); reddishpapillatetrichomeson the new growth of the S. arboreumandS. robustifronsspecies groups; golden dendritictrichomes in the S. pseudocapsicum species group; densely brancheddendritic trichomesin theS. arenariumspecies group.Untilthese trichome types are betterunderstoodstructurallyand developmentally it seems most reasonablenot to use them in phylogenetic analyses. Trichome morphology has been a mainstay in Solanum taxonomy (Seithe, 1962, 1979), but careful examinationshows thatit cannotbe relied upon to the extent that it is now used, particularilyin this group. Trichome morphology of the stellate-haired groups (subgenusLeptostemonum)has been relatively better studied, and a few studies exist of non-stellate-haired groups (Edmonds, 1982; Seithe & Anderson, 1982; Bohs, 1994). It is quite clear however that much remains to be done with trichomemorphology and evolution in Solanum, particularlywith groups of nonspiny species without stellate hairs.

tetraploidthroughoutits range.Materialreportedas S. superficiens (a synonym of S. spirale) from Bogor, Java,Indonesia(see TableVI), is actuallyS. diphyllum, a nativeof Mexico commonlycultivatedas anornamental shrubthroughoutthe tropics and subtropics. Chromosome size has been used to support the monophyly of some groups within Solanum (Bohs, 1994). Cyphomandra(Solanumsect.Pachyphylla)and its sistergroup,Solanumsect. Cyphomandropsis,both have uniformly large (3-14 gfn with an average of 8 pam)chromosomeswith correspondinglylargeamounts ofDNA (Bemardello & Anderson, 1990; Bohs, 1994; Pringle& Murray,1992;Moscone, unpubl.).Members of sect. Geminatahave chromosomes of a more typical Solanummorphology:very small (less than4 tm) andindistinct.However,an intriguingexceptionto this arethe chromosomesofS. tanysepalum,which arequite large and look more like those of a typical Cyphomandra.Detailed measurementsare lackinghowever, andthese may prove to be of greatutility in the assessment of chromosomesize as an informativecharacter in sect. Geminata.

CHROMOSOMES

Species of section Geminataoccur throughoutthe Neotropics,fromca. 20? N latitudeto nearly32?S latitude (Fig. 12). Species of the section occurin all countries of continentalSouthAmericaandthroughoutthe WestIndies.A single species,Solanumn spirale,is widespreadin the Old WorldAsian andAustraliantropics, rangingfrom Chinato Australia.The greatestspecies diversity in sect. Genminatais found in the western Amazonbasin,on the easternslopesof the Andes.Other areas of high species diversity are montane coastal VenezuelaandtherelictAtlanticmoistforestsof eastern Brazil.In SouthAmericamost species arefoundin relatively low elevationforests,andmany species occurin the Amazonbasin, but in CentralAmericathe groupis largelymontane.This may reflectthe geological youth of CentralAmerica, andthe possible derived statusof the species occurringthere.Most species of the section, in both South and CentralAmerica, grow in areas of high rainfall (2500 to 12000 mm per year), but some species are only found in dry habitats.Refer to Table VII for the distributionsof membersof the section in differenthabitats(life zones) in the Neotropics. Speciesof sectionGeminataareunusualin Solanum in beingtreesandshrubsof forestinteriors.Many,if not most,otherSolanumspeciesareplantsof disturbedareas andareoftencharacterized as noxiousweeds. Roadsides

Polyploidy has been importantin the evolution of some groupsof Solanum,e.g., sect.Petota (see Correll, 1962; Magoon et al., 1962; Hawkes & Hjerting,1969; Hawkes,1979;Hawkes& Hjerting,1989;sect.Solanum, see Edmonds,1972, 1979).Thebase chromosomenumber in Solanum is n = 12. Three chromosome counts representingtwo species of sect. Geminatahave been reportedin previousliterature(D'Arcy, 1969; Randall & Symon, 1976). Aceto- and lacto-propionicorcein squashesof pollen mothercells fromplantsgrowingat the Bailey HortoriumConservatoryandcollectedin the field in modified Camoy's solution (4:3:1 chloroform: ethanol:acetic acid) have raisedthe numberof counts to 58 andthe species countedto 40. Documentedchromosome counts for species of sect. Geminataarelisted in TableVI. Voucherspecimens aredocumentedin the individualspeciesdescriptions,andaredepositedin BH, BM, or MO. All species, except S. spirale, are consistently diploid with n = 12. Thus speciation and evolution in sect. Geminatahas largelyoccurredatthe diploid level. Solanumspirale is tetraploid,with n = 24. Only populationsfrom Australiahave been counted, andS. spirale occurs from Australia through Indochina to India. Authentic material from Indonesia, India, or Indochinais needed to determinewhetherS. spirale is

ECOLOGY AND NATURAL HISTORY HABITATS AND DISTRIBUTION

23

ECOLOGY AND NATURAL HISTORY

Table VI Chromosome numbersin sectionGeminata.Collectionsby Knappandco-collectorsaredesignatedby K followedby number:details canbe foundin specimenscited.BH vouchersreferto plantsgrownin the greenhousesat the L.H.BaileyHortorium, Ithaca,NY. TAXON Solanum abitaguense S. amblophyllum S. aphyodendron S. arboreum

S. campaniforme S. confertiseriatum S. confine S. cucullatum S. diphylluni S. dissimile S. erosomarginatum S. foetens S. gratum S. hypaleeurotrichum S. hypocalycosarcum S. leptopodum S. leptorhachis S. leucocarpon

S. maturecalvans S. nudum

S. oblongifoilun S. oblongum S. ombrophilum S. oppositifolium S. pastillum S. psetudocapsicum S. ramonense S. ripense S. robustifrons S. rovirosanum S. sessile

S. sieberi S. spirale S. tanysepalum S. tenuiflagellatum S. triste S. tuerckheimii S. turgidum S. vaccinilflorum S. yanamonense

NUMBER n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n 12 n = 12 n = 12 n = 12 n= 12 n= 12 n = 12 n = 12 (2 n = 24) n = 12 n 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 24 n = 24 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12 n = 12

SOURCE Ecuador. Tungurahua.Bafios-Mera. (K 6177) Peru. Lima. Huarochiri.Rio Macachala. (K 6309) Panama. Chiriqui. Fortuna. (K 4136) Ecuador. Tungurahua.Rio Topo. (K 6181) Costa Rica. Heredia. Finca La Selva. (K 802) Panama. Canal Area. Pipeline Rd. (K 4862) Venezuela. Tfchira. Las Dantas. (K 6835) Venezuela. Bolivar. Gran Sabana. (K 6734) Ecuador.Los Rios. Rio Palenque.(K 6220, 6226, 6228) Peru. Pasco. Rio Palcazu. (K 6649) Ecuador. El Oro. nr. Las Balsas. (K 6266) Florida. Alachua. Gainesville (D'Arcy, 1969) Florida. Tampa (BH 85:234) Venezuela.Merida.Chorreralas Gonzalez.(K 6817) Venezuela. Trujillo. Bocon6-Trujillo. (K 6777) illo.llo. Venezuela. Trujillo. Bocon (K 6788) Venezuela. Merida. Chachopo. (K 6799) Venezuela. D.F. P.N. El Avila. (K 6872) Ecuador. Loja. JardinBotanico. (K 9085, 9094) Ecuador. El Oro. nr. Las Balsas. (K 6265) Peru. Loreto. Yanamono. (K 6610) Ecuador. Pichincha. Tinalandia. (K 6160) Colombia. Cundinamarca.(K 889, BH 79:376) Venezuela. Tfchira. Las Dantas. (K 6836) Ecuador. Morona-Santiago.Gualaquiza. (K 6241) Peru. Cuzco. Ollantaytambu.(K 6351) Costa Rica. Puntarenas.P.N. Corcovado. (K 887) Panama. Veraguas. Rio Sta. Maria. (K 4325) Venezuela. Merida. La Mucuy. (K 6791) Ecuador. Napo. Rio Latas. (K 6200) Peru. San Martin. Cufiumbuque.(K 6480) Peru. San Martin. Tarapoto-Yurimaguas.(K 6515) Ecuador. Loja. Loja-Zamora.(K 6247) Peru. Pasco. Rio Cacazu. (K 6628, 6636) Venezuela. Aragua.P.N. Henri Pittier.(K 6842, 6847, 6857) Peru. Loreto. Yanamono. (K 6618) Peru. Pasco. Laguna. (K 6656) Costa Rica. Puntarenas. Monteverde. (K s. n., 6063) Cultivated. Gerasimenko & Reznikova, 1968; Randall & Symon, 1976 Panama. Chiriqui. Pate Macho. (K 4270) Venezuela. Merida. La Carbonera.(K 6813) Peru. San Martin.Cufumbuque. (K 6474) Costa Rica. Heredia. Finca La Selva. (K 804) CostaRica.Puntarenas. Monteverde.(K 844, 848, 861) Ecuador. Napo. Cascada San Rafael. (K 6207) Peru. Pasco. Oxapampa. (K 6316) Peru. Cuzco. Quincemil. (K 6391) Peru. Amazonas. Rio Chiriaco (Imaza). (K 6569) Venezuela. Falc6n. Chichiriviche. (K 6704, 6707) Australia. (BH 81:139) Australia. Queensland. Toonumbar.(Randall & Symon, 1976) Venezuela. Aragua. P.N. Henri Pittier. (K 6856) Venezuela. D.F. above Carayaca.(K 6859) Venezuela. Sucre. Cumanacoa.(K 6750) Costa Rica. Puntarenas.Monteverde.(K 610, 872) Venezuela. Sucre. Manacal. (K 6765) Costa Rica. San Jose. Cerrode la Muerte.(K 790) Peru. Loreto. Yanamono. (K 6613)

FLORANEOTROPICA

24

I

WI

-

r -L77

J.

---Jl-

* I3

-- .

!3

g!Je

I

-r

,

?.

g

I

l

l

CT

I-

-

-

i Z

-

- I

.

_^

--

w

--

-

-

....: ........ ....... :.........

FIG. 12. Worldwide distribution of Solanum section Geminata.

Table VII Distribution of species of section Geminata in habitats in the Neotropics. Forest types modified from Holdridge (1967) and Heuck & Seibert (1972). For habitats and specifics of individual species, refer to the species descriptions. The total in this table exceeds the number of species accounts in this monograph because many taxa occur in more than one habitat. HABITAT

NUMBERS OF SPECIES

above tree line (incl. paramo) montane rain forest premontane rain forest lowland tropical rain forest tropical and subtropical deciduous forest savannah& savannahedges (incl.camposlimpios& cerrados) Araucaria angustifolia forests

10 species 30 species 45 species 49 species 14 species 6 species 3 species

intropicalAmericaareprimehabitatsformanysolanums, particularlythe spiny species (see Nee, 1979;Whalen, 1979;Whalenet al., 1981). Those species now so common along roadsidesprobablywere rarebefore widespreadhabitatdestructionby manso alteredandincreased theirhabitat.Most species of sect. Geminataareprimary forest treelets and shrubs, often growing along small

streamsor in old light gaps. They rarelygrow in areas of high light intensity,or where the soil is likely to dry out for long periods.Light gaps createdby tree falls or by small streams in the forest understoryare natural andimportantpartsof the tropicalforesthabitat,andare essential in the maintenanceof the system (Hartshorn, 1978, 1980, 1989, 1990; Denslow, 1987). Many sec-

25


Table VIII Hymenopteraknown to vibrateSolanum flowers (classification mod ified from Michener, 1979; for referencessee text . HYMENOPTERA COLLETIDAE COLLETINAE:Caupolicana, Colletes, Ptiloglossa HYLAEINAE: Hvlaeus STENOTRITIDAE:Stenotritus HALICTIDAE HALICTINAE:4 ugochlora, Augochlorella, Caenaugochlora, Augochloropsis, Halictus, Lasioglossum, Neocorynura, Pseldaugochloropsis, Evvlaeus NOMIINAE: Nomia OXAEIDAE: Mesoxaea, Nofoxaea, Protoxaea, Oxaea ANDRENIDAE PANURGINAE: Protandrena, Psaenythia ANTHOPHORIDAE ANTHOPHORINAE:Anthophora, Centris, Epicharis, Exomalopsis, Melissodes, Amegilla XYLOCOPINAE:Xy,locopa APIDAE BOMBINAE: Bombiis, Eulaema, Euglossa MELIPONINAE:Melipona, Trigona

ondaryspecies germinateandgrow in these light gaps, but do not persistwhen the forestcanopy closes. Some species of sect. Geminatagerminateandgrow in these areas,but do persistas forestplants.Membersof theS. confine species group are all plants of shady forest understory,as are many other species in the section. The understoryspecies, both those startingin light gaps andthose fromdarkinteriors,can be classified as sparse(Rabinowitz,1981). Sparsespecies arethosethat arenot common locally, but may grow in few to many habitats,andover a large or narrowgeographicrange. Species of sect. Geminataare often both rareand endemic (sensu Gaston, 1994) and are also likely to be vulnerable or threatened(Davis et al., 1986), but the degree to which this is the case remains to be tested. Particularforestspeciesof sect.Geminataareoftenconfined to a single forest type, e.g., cloud forest, varzea forest, etc. Where a particularspecies is found, individuals are often ratherscarce and difficult to locate. Statementsaboutthe rangeof habitatsor the geographical rangeof species are difficult to make at present,as so few collections exist for any but the most common roadside species. Some of the forest species of sect. Geminataareknown from only a few collections, perhapsdue to theirprimaryforest habitat,but also due to their small populationsizes where they do occur. Extreme examples of these sorts of species areSolanum dasl,neuronfromthe borderof GuatemalaandMexico, S. vanamonense fromeaster Peru,andS. tenuiflagellatum from montanecoastal Venezuela. Not all species of sectionGeminataareprimaryforest plants.Mostmembersof theSolanumnudumspecies

group are shrubsand small trees of secondaryforests androadsides.Thesespeciesoftengrowin densemonospecificstandsandareusuallyrelativelycommonwhere they occur(with the possible exceptionofS. reitziiand S. intermediumof southeasternBrazil).Theserelatively weedy species grow in recenttreefalls in the forestbut do not persist in these habitatsonce the canopy closes andthe sitebecomesshady.Thesecondaryforestspecies of sect. Geminataoften attainmuchgreatersizes (when left uncut)thando the primaryforest species.Solanum acuminatum,a memberof the S. nudumspecies group, occasionally grows to be a tree 15 m tall and 20 cm in diameterin the ChanchamayoValleyin centralPeru. POLLINATION Many, if not all, solanums are buzz-pollinatedby bees (Bowers, 1975;Buchmann,1983;Buchmannet al., 1977;Linsley, 1962;Linsley& Cazier,1963, 1972;Liu et al., 1975; Michener, 1962). Vibratilepollination is relativelywidespreadin angiosperms,occurringin about 200 genera(Buchmann,1983). This phenomenonwas first documentedin Solanlumin 1962, but was known from other genera much earlier(Michener, 1962; see discussion in Buchmann, 1983). Bees of many families possess the ability to vibrateSolanumanthers(see TableVIII andreferencesabove). Interestingly,honey bees (Apis mellifera L.) are unable to vibrate the anthers,and arethus not good solanumpollinators.Bees extractpollen from the poricidal anthersby vibrating theirindirectflightmuscles locatedin the thorax,while they firmly graspthe anthercone and often "milk"the antherswiththeirmandiblesandlegs (Buchmann,198:3;

FLORA NEOTROPICA

26

..

A

B

FIG. 13. Bombus worker buzzing a Solanum pastillum flower. A. buzzing. B. cleaning and packing pollen in the scopa.

Macior, 1964; Michener et al., 1978) (see Fig. 13A). Cloudsof pollen arereleasedanddepositedon the sternum of the bee. The pollen is cleaned from the accessiblepartsof thebee andplacedin the scopaeitherwhile the bee is still hangingby a tarsalclaw fromthe flower (Fig. 13B), after the bee lands on a nearby leaf, or in flight (see Micheneret al., 1978, for mechanics). Pollination in Solanum thereforeis sterotribic. In some large-floweredspecies of Solanumonly largebees, such as Centris,Bombus, andXylocopa, are able to vibrate theentireanthercone andthuseffectpollination.Smaller bees often vibrateone antherat a time, such that their bodies do not make contact with the stigma. In these cases, small bees are ineffective as pollinatorsand are moreproperlyconsideredpollen thieves (see Eickwort, 1967; Whalen & Costich, 1986). Small bees and bees unableto vibrateanthersoften gleanpollen scatteredon thecorollalobesby buzzingbees (Linsley& Cazier,1963; Wille, 1963;Knapp, 1986a;Whalen& Costich, 1986). Pollen is collected for larval food and is the most importantproteinsourcefor all bees (Buchmann,1983; Michener, 1974). The only floral reward offered by solanums to their pollinators and/or floral visitors is

pollen. Nectar is never found in these flowers (see Buchmannet al., 1977; Knapp, 1986a). The anthersof most species ofSolanumarerelativelythick-walledand tough, as one might expect when bees manipulateand presumablycoulddamagethe anthers.Antherson older flowers of membersof sect. Geminataoften have damage dueto smallgleaningbees orto thosetryingto chew intothe anthersto "illicitly"removepollen(see Fig. 14). The antherwalls are usually brightyellow or orange, which is not due to pollen content of the anther.The pollen itself is pale cream, and the bright color of the antherwalls may serve to attractbees to the flower, or to deceive bees as to the contents of the anther(Vogel, 1978). Bees are apparentlyable to assess the pollen contentof anthersbefore buzzing them, as I have seen Bombusworkersapproachflowers,hovernearthemand then fly away. Invariablythese were flowers thatwere severaldays old, or thathadbeen visited by manybees previously. Pollen may have some odor, as in certain Myrtaceae(van Wyk,pers. comm. to D. Charlesworth; Kevan& Lack,1985),Dodecatheon Porsch, (Primulaceae; 1954), and some solanums(Buchmann,1983; D'Arcy et al., 1990), or perhapsthe bee perceives a change in

27


~~~~i. i 2

i...............................................

~~~~: ~.~... ~,~~ ,

...

~,

*.

;.

,

..........

ti'?

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FIG. 14. Damage to anthers of older flowers of Solanum sessile (Knapp & Mallet 6625: Peru) from pollencollecting bees.

the staticelectricity of the antherbroughtaboutby repeatedbuzzing(Buchmann,pers.comm.).SomeSolanum species have ultra-violetabsorbingtissue in the corolla nearthebaseof theanthercone (Utech& Kawano,1975; Buchmannet al., 1977). The anthersthemselves are stronglyultra-violetabsorbingin S. nigrum(Utech & Kawano, 1975). No members of sect. Geminatahave been tested for ultravioletabsorptionor reflectance. Flowers of species of section Geminata are quite small as solanums go, and thus even very small bees can function as effective pollinators. In a field study conducted in Monteverde, Costa Rica (see Knapp, 1986a, for details of the site andthe study),workersof Bombusephippiatuswere the most important(numerically) floral visitors of the forest species. Workersof thehighlyeusocialstinglessbeeMeliponafasciatawere most importantat the secondarygrowth species. Bagging studiesshowed thatthese bees also effected most of thepollinationin the species studied(Knapp,1986a). Other smaller bees also visited the flowers of these species(see TableIX), butwere not as importantin pollinationandoften only gleanedpollen fromthe corolla lobes (Knapp, 1986a). In a low elevation area in Ven-

ezuela, many small bees were foundbuzzingSolanum sieberi. The lack of large bees in this sample may be due to small samplesize andshortcollectingtime at the flowers. See Table IX for details of bees collected on members of sect. Geminata. In Monteverde,CostaRica, the second growthspecies of section Geminata were visited primarily by Meliponafasciata, a highly eusocial bee that recruits to food resources(Michener,1974;Hubbell& Johnson, 1978; Knapp, 1986a;Roubik, 1980). Much movement of bees is between flowers of the same plant,but since the plants often grow in dense monospecific stands, inter-plantmovement is common as well. In the forest species, on the otherhand,individualBombusworkers appearedto go fromone individualto anotherof thesame species. This was particularly obvious in Solanum pastillum,where visits were common enoughto be assessed. These bumblebees, markedwith dots of paint, werenot observedvisitingothersolanumsor otherflowers in bloom in the area. In the area, many other individuals of Bombus visited the flowers of a species of Hoffmannia(Rubiaceae),andnevervisited the flowers of S. pastillum in thatparticularforagingtrip.Vibratile

28

FLORA NEOTROPICA

Table IX Bees collected on species of section Geminata. MV-Monteverde, Puntarenas,Costa Rica; CH-Parque Nacional Morrocoy, Chichiriviche, Falc6n, Venezuela: all insects in the Cornell University Insect Collection (Lot no. 1146). Determinations by J. Labougle (Bombus), G.C. Eickwort (Halictidae, Anthophoridae), and D. Roubik (Apidae). TAXON

FLOWER VISITOR

Solanum aphyodendron MV

Meliponafasciata costaricensisCockerell(Apidae) MeliponamelanopleuraCockerell(Apidae) Neocorynura(Neocorynura)sp. (Halictidae) LasioglossumkatyaeMcGinley (Halictidae) BombusephippiatusSay (Apidae) Caenaugochlora(Ctenaugochlora)sp. (Halictidae) BombusephippiatusSay (Apidae) Caenaugochlora(Ctenaugochlora)sp. (Halictidae) Meliponafasciata costaricensisCockerell(Apidae) Exomalopsissp. (Anthophoridae) BombusvolucelloidesGribodo(Apidae) BombusephippiatusSay (Apidae) Augochloropsisvesta (Fabr.)(Halictidae) Augochloropsissp. 1 (Halictidae) Augochloropsissp. 2 (Halictidae) Exomalopsissp. (Anthophoridae) BombusephippiatusSay (Apidae)

S. pastillum MV S. pertenue MV S. rovirosan um MV

S. sieberi CH

S. tuerckheimii MV

pollination is a learned technique in eusocial bees (Buchmannet al., 1977), and the behaviorofBombus workerson flowers of sect. Geminatain Monteverde may be an example of the behavioralspecializationof individualworkers(see Heinrich, 1976, 1979; Knapp, 1986a). The primaryforest species visited byBombus occurin rare,widely scatteredpatches,andconstitutea good resource for a bee exhibiting flower constancy (Grant, 1950). Polylectic bees visiting Solanum in a desert site in the southwesternUnited States were remarkablyconstantto those species (Linsley & Cazier, 1963). Flower constancy by tropical bees has been suggested as a mechanismallowing manytropicalbee pollinatedplantsto survive andreproduceat low densities (Janzen, 1971). Foragingbehaviorof individual bees on flowers of low elevation species of sect. Geminatais not known. Bombusis not numerousoutside of the cool cloud forests in the tropical zone, but euglossine bees are common in low elevation tropical forests. Female euglossine bees have been shown to exhibit great flower constancy in lowland Costa Rica (cf. Janzen, 1971), but theirvisits to membersof sect. Geminatahave never been studied.Studiesof pollination in these sparse forest species requirea great deal of time andpatience,since bees do not visit the flowers very often (see Knapp, 1986a). Self-compatibility is widespread in Solanum (see Whalen& Anderson,1981,fora reviewofincompatibil-

ity in the genus). The potatoes and their relatives are exceptions to this rule (de Nettancourt, 1977), as are the wild species of sect. Pachyphylla (Cyphonandra sensu Bohs, 1994: all species now transferred to Solanurm,see Bohs, 1995). The few membersof sect. GeminatathatI have testedhave been self-compatible, butnot autogamous(S. diphyllum,S. aphyodendron,S. pertenue, S. pseudocapsicum,S. spirale). Very few of the species of sect. Geminataas treatedherehave been tested,however,so generalconclusionsarepremature. FRUIT DISPERSAL No rigorous studies of seed or fruit dispersal in Solanumin the Neotropicshave been done, despitethe greatdiversityin fruitsize, color, andgeneralmorphology in the genus (but see Symon, 1979b, for Australian solanums).Berriesof species of sect. Geminataare usuallyrelativelysmall(ca. 1 cm in diameter)andgreen, turningyellow-green when they areripe. Ripe berries are difficult to find, suggesting thatthey ripenand are takenby frugivoresratherquickly.Many species have berrieswhich,whenripe,easily detachfromthepedicel. No speciesthatI have seen have fruitsthatabsciseat the base of the pedicel, releasing the fruitandpedicel as a unit, as occursin some othersections of the genus (see Nee, 1979;Whalen, 1979). If an inflorescencecontains severalberries,theseripensequentiallyandratherslowly. InMonteverde,CostaRica,fruitsof all membersof sect.

29


A

B

FIG. 15. Long and short-styled flower morphs in Solanum section Geminata.

Geminataaretakenby both birdsandbats. The berries of S. aphyodendron(as S. nudumin Dinerstein, 1986) are an importantcomponent of the diet of Sturnira ludovici, a small frugivorous bat (Dinerstein, 1983, 1986). These fruits have very high CHO values and aretakenpreferentiallyduringlactationof female bats (Dinerstein,1986). Emeraldtoucanets(Aulacorynchus prasinus) have been reportedas commonly feeding on the fruitsofS. aphyodendron(as S. nudum)andmasked tityras(Tityrasemifasciata)as occasionally feeding on the same species (Wheelwrightet al., 1984). I also observed band-tailedpigeons (Columbafasciata) feeding on the fruitsof this species, which is commonin the second growthin montaneCosta Rica. Seeds of all the forestspeciesof sect. Geminatagrowingat Monteverde were also found in bat feces (Dinerstein, 1983; pers. comm.). Bats use trailsand forest openings as flyways and often defecate in flight. The distributionof these solanumsin light gaps and along trailsmay reflect this behavior.Seeds of several species of sect. Geminata germinateafterpassagethroughbatguts,indicatingthese animals are probably good seed dispersers (but see Wheelwright& Orians, 1982, for a discussion of what constitutesa "good"seed disperser).Some species of sect. Geminata,notably those of the S. arboreumspecies group, have berries smelling strongly of wintergreen when they are ripe (also true in sect. Pteroidea, another forest understory group, see Knapp & Helgason, 1997). Whatanimalrespondsto this smell is not known. Fruitsof these species are often found on thegroundbeneaththe plants,andareperhapsdispersed by small rodents living on the forest floor. The fruits and seeds of the species with brightly colored berries (S. pseudocapsicum species group and S. spirale) are almostcertainlytakenanddispersedby birds.The fruit of S. pseudocapsicum growing in its native habitat

(Paraguayand Argentina)is much dullerin color than thatof cultivatedplants.Muchmorework is needed on both frugivoryand seed dispersal in sect. Geminata. SEX EXPRESSION Derived sexual systems in Solanum have become of interest recently (Anderson, 1979; Anderson & Levine, 1982; Whalen & Costich, 1986; Anderson & Symon, 1989;Zavada& Anderson,1997;Knappet al., 1998), particularlyin light of field studiesandtheoretical work on the evolution of these systems in angiosperms (Bawa, 1980; Bawa & Beach, 1981; Charlesworth, 1984; Renner& Ricklefs, 1995). Many species of Solanumbear only hermaphroditicflowers, all capable of functioningboth in pollen donation and fruit set.Differentformsof flowerswererecognizedby Dunal (1813, 1816, 1852), when he noticedthe differencesin style length in flowers of the same specimen. Many insubgenusLeptostemonum, Solanumspecies,particularly are andromonoecious,bearinghermaphroditicand female-sterileflowers on the same plant(for a classification of sexual systems in angiosperms see Bawa & Beach, 1981). The two floral morphsare easily distinguished: the female-sterile flowers have the style included in the anthercone (Fig. 15B), while in the hermaphroditicflowers,the styleprojectsbeyondtheanther cone (Fig. 15A). The morphsare generallyreferredto as short-styled(SS) flowers and long-styled(LS) flowers. For a review of the literaturedescribingstylarheteromorphisminSolanumsee Whalen& Costich(1986). Varioushypothesesrelatingto the evolutionof these derivedsexualsystemsinSolanumhavebeenadvanced. Symon (1979a) suggested thatsince pollen is the only rewardoffered to pollinatorsby Solanumflowers, the production of excess male flowers should increase pollinatorvisitationratesandthereforeincreaserepro-

30

ductive success. The enhancementof pollination efficiency by productionof excess pollen (i.e., male flowers) has been suggested for the andromonoeciousspecies S. marginatum L. f. (Dulberger et al., 1971). Coleman& Coleman(1982), workingin BrazilwithS. palinacanthumDunal, speculatedthat andromonoecy in thatspeciespromotedoutcrossing.Whalen& Costich (1986) review severalhypothesesconcerningthe evolutionof andromonoecyin Solanumand suggest thatit is unlikely that andromonoecypromotes outcrossing, protects ovaries from predators,or enhances pollen depositionon stigmas. They concludethatthe production of excess staminateflowers aids in pollinatorattraction,and thatthe suppressionof gynoecia in those flowers providesa flexible mechanismfor controlling fruit set. Diggle (1991, 1993) has shown that both phenotypicandgenetic plasticitycontributeto the proportionof female-sterileflowers producedin response to both pollination and fruitset. Selection for increasingcross-fertilizationhas generallybeen consideredthe most importantdrivingforce in the evolution of andromonoecy (Heithaus et al., 1974). Problems with this explanation are many (Primack& Lloyd, 1980;Bawa & Beach, 1981;Bertin, 1982;Renner& Ricklefs, 1995), andit has been shown that in a self-compatible species, andromonoecywill actually always restrict and not enhance outcrossing (Whalen & Costich, 1986). Andromonoecy may be maintainedin Solanumby selection againstthe loss of stamens, as the stamens provide the sole reward for potentialpollinators,and areessential in pollinatorattraction. Bertin (1982) has suggested that the role of pollen as a food rewardpreventsthe evolution ofmonoecism from andromonoecism.No strictly monoecious Solanum species are known. Truedioecy has been reportedin several unrelated sections of Solanum in both Australia and Central America(Anderson, 1979; Anderson& Levine, 1982; Anderson & Symon, 1989; Knapp et al., 1998). The Australian species were originally thought to be androdioecious(Symon, 1970, 1979), with male flowers on one plantandhermaphroditic flowerson another, as the female flowers appearto have functional,pollenfilled anthers.It has been shown however thatthe pollen produced in the anthers of female flowers is inaperturateanddoes not germinate(Anderson, 1979; Anderson & Symon, 1989). Dioecious species in Solanumare an interestingcase: they occur in several unrelatedgroups and appearto have evolved directly from andromonoecious or hermaphroditicancestors withoutpassingthroughthe intermediatestages generally assumed(Bawa, 1980;Bawa & Beach, 1981;Ross, 1982). A model for testing the evolution of dioecy in

FLORA NEOTROPICA

Solanumwas proposedby Knappet al. (1998), and it is clear that Solanum is an ideal group with which to test hypotheses about the evolution of derived sexual systems in angiosperms. Derived sexual systems have very rarelybeen describedfor most membersof sect. Geminata,save for comments contained in the species descriptions of Dunal (1813, 1816, 1851) and Sendtner(1846) (but see Knapp et al., 1998, for a complete descriptionof themorphologyof dioecyinSolanumconfertiseriatum). Most work on this subject in Solanumhas been done in subgenusLeptostemonum. Inthe courseof the preparationof this monographI found that most species of sect. Geminatahave short-styledandlong-styledflowers in the same inflorescences. These species often set few fruit per inflorescence, thus strengthening the circumstantialevidence that they are indeed andromonoecious.I have neverseen short-styledflowerssetting fruitin the field or in the greenhouse.The evidence for andromonoecyin sect. Geminata,though strong, remainsto be tested experimentallywith pollinations in the field or greenhouse in most of the species. The distributionof short-styledflowers on a plant and in an inflorescence in species of sect. Geminatais not as obvious as in many members of subgenus wherethebasalflowersareoftenlongLeptostemonum, styled and the rest are short-styled.In sect. Geminata a few generalizationscan be made. The first inflorescencesproducedby a reproductiveshootareoftencomprised only of short-styledflowers. Subsequentinflorescences will have both floral morphs. Within an inflorescence, short-styledflowers are seemingly randomlyproduced,sometimesat the base andsometimes nearthe tip. Theproductionof short-styledflowersmay be under some environmentalcontrol as it is in other solanums(Wakhloo, 1975a, 1975b, 1975c; Whalen& Costich, 1986) or some genotypic plasticity may be involved(Diggle, 1993;Knappet al., 1998). Species of sect. Geminatagrowingin the Bailey Hortoriumgreenhouses seem to have higherproportionsof short-styled flowersthanplantsof the same species I have collected in the field. Whetherthis distributionis age-relatedor environmentallyinducedis not known. In the Solanum sessile species group, the entire range of sex expression is found: from plants with all flowers(S.turgidum)to dioeciousplants hermaphroditic (S. confertiseriatum) (Knapp,1991a). InS. rovirosanum in Costa Rica, young plantsproduceonly short-styled flowers. Largerolder plantsbearonly hermaphroditic flowers,with an occasionalshort-styledfloweron some inflorescences. Solanum sessile in eastern Peru and Ecuadorbears both long and short-styled flowers on the same inflorescence, and appears to be andro-


31

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S|-|S>>a 2 cm in diameter:72, 73, 76 Berry red or orange at maturity:6, 8, 9, 24 Seeds flattened-reniform,with incrassatemargins:1, 2,3,4,5,6,7,8,9,10,11, 12,13,14,15,16,17, 18, 19,20,21,22,23,24,25,26,27,28,29,30,31,32, 33, 34,35, 36,37, 38,39,40,41,42,43,44,45,46 Seeds ovoid-reniform, the embryo clearly visible: 47,48,49,50,51,52,53, 54, 55, 56, 57, 58, 59,

TAXONOMIC TREATMENT43

60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116 117, 118, 119, 120, 121, 122

I. Solanum oblongifolium species group (S. clivorum, S. hypaleurotrichum,S. oblongifolium, S. venosum). Fig. 19A-C

opposed except occasionally in S. clivorum;pedicel scars closely spaced and overlapping.Buds globose, the calyx thick and appearingwoody when dry.Flowers white, large and usually waxy, the petals planarat anthesis. Fruit green and hard at maturity;fruiting pedicels erect to deflexed from the weight of the fruit. Seeds flattened-reniform,pale yellowish-brown, very large, with prominentlyincrassatemargins.

Distribution. Andean,Venezuelato Peru.Members of the Solanum oblongifolium species group are superficiallyreminiscentof species belongingto Solanum Treelets or small trees, young stems and leaves sect. Brevantherumin their large, complex infloresdenselydendritic pubescent.Sympodiausuallyplurifoliate, cences. However, membersof sect. Brevantherumalin Solanumclivorumdifoliateandthe leaves geminate. ways have stellate or echinoid pubescence (see Roe, Leaves large(to 30 cm) andrepand,the apex acute,the 1971) and the inflorescences arise from a dichasial base occasionallysessile andsomewhatauriculate,leaf branchfork (see Knapp, 1989) insteadof being lateral pubescence always dendritic,the trichomes transpar- as they are in the S. oblongifolium species group. In ent to beige or reddish-brown.Inflorescenceslargeand this species groupin the Andes of Ecuadorhybridizabranched,usuallyterminal,occasionallylateral,not leaf- tion appearsto be relatively common (see below).

Key to the species of Solanum oblongifolium species group 1. Trichomes of stems dendritic, transparent. 2. Flowers waxy, 1.2-2 cm diam.; fruit to 2 cm diam., green and hard at maturity; sympodial units plurifoliate .............................................................................................................................. 3. S. oblong f liu m 2. Flowers membraneous, 1-1.1 cm diam.; fruit 1-1.2 cm diam., green and soft at maturity; 1. S. clivorum sympodial units difoliate; the leaves usually geminate .................................................... I. Trichomes of stems Christmas-tree-like or dendritic, reddish or beige, never transparent. 3. Trichomes reddish, those of leaf undersides dendritic; leaves with 10-20 pairs of main lateral v ein s .................................................................................................................................................. S. venosum 3. Trichomes beige, those of leaf undersides Christmas-tree-like;leaves with 6-8 pairs of main lateral veins ...................................................................................................................................... 2. S. hypaleurotrichum

1. Solanum clivorum S. Knapp,Novon 2: 341. 1992. Type.Peru.La Libertad:BetweenHuamachucoand Cajabamba,3000-3200 m, 16 Mar 1948,Ferreyra 3059 (holotype, USM; isotypes, IBE, MO, US). Fig. 20 Bushy shrubs, 2-3 m tall; young stems and leaves densely pubescentwith dendritictrichomesca. 0.5 mm long; bark of older stems reddish or green, glabrous. Sympodial units difoliate, geminate, or appearing plurifoliatedue to rapidinflorescence growth.Leaves elliptic,commonlywith severalaxillaryshoots,glabrous (occasionallywith scatteredsimpleuniseriatetrichomes on the lamina)andwith a few dendritictrichomesalong the main veins adaxially,densely pubescentwith dendritictrichomesabaxially;majorleaves 13-21 (-30) cm long, 6-9(-17) cm wide, with 7-9 pairsof main lateral veins, these dryingyellowish, the apex acute, the base acute;petiole 2-3 cm long; minorleaves differingfrom the majorsonly in size, 7-10 cm long, 3-4 cm wide, the apexacute,thebase acute;petiole 1-2 cm long.Inflorescences oppositethe leaves or appearingshoot-terminal, 3-7 cm long, many times branched,20-40 flowered, denselypubescentwithdendritictrichomes;pedicelscars

unevenly spaced 1-2 mm apart.Buds globose, the corollaonly halfwayexsertedfromthe calyxtube.Pedicels at anthesis erect, tapering,6-8 mm long, ca. 0.5 mm diam.at the base, densely pubescentwith soft dendritic trichomes like those of the rest of the inflorescence. Flowerswith thecalyxtubeconical, 1-1.5 mm long, the lobes deltate, 0.5-1 mm long, densely pubescentwith dendritictrichomes;corollawhite, 1-1.1(-2) cm diam., lobed 1/2 way to the base, the lobes planarat anthesis, denselypubescenton abaxiallobe surfacewith minute, dendritictrichomesor occasionally glabrous;anthers 1.5-2 mm long, 1-1.5 mm wide, poricidal at the tips, the pores not opening to slits; free portion of thefilamentsca. 0.5 mmlong,thefilamenttubeca. 0.5 mm long, with 5 triangularprojectionsca. 0.5 mm long alternating withtheanthersandclosely investingthestyle;ovary glabrous;style 3-4 mm long, glabrous;stigmacapitate, the surfaceminutely papillose. Fruit a globose, green berry,1-1.2 cm diam.;fruitingpedicels woody, erect, 1.5-1.7 cm long, ca. 1.5 mm diam. at the base. Seeds darkreddish-brown,flattened-reniform with thickened 3mm 2-2.5 mm the surfaces wide, margins, long, minutely pitted. Chromosomenumbernot known.

44

FLORA NEOTROPICA

. S_..j'

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TAXONOMIC TREATMENT

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Distribution (Fig. 21). N Peru in the province of Cajamarca, in montane forest at 2000-3200 m. Specimens examined. PERU. CAJAMARCA: Prov. Cutervo, Laguiac, rd. to Cochabamba, 2000 m, 26 Feb 1985, Llatas Quiroz 1178 (F); Cajabamba, Finca Zil, 2500 m, 22 Aug 1985, Mostacero L. & Guerra L. 63 (HUT, MO, NY); Cajamarca, between Matara and Namora, 2600 m, 16 Aug 1973, Sdnchez Vega et al. 1217 (NY); prov. Cutervo, distrito San Andr6s, above the caves, 2500 m, 13 Oct 1987, Sdnchez Vega 4510 (BM, F); prov. Cutervo, La Pucarilla, between Socotra and San

Andr6s,2500 m, 3 Nov 1991,SdnchezVegaet al. 5960 2600 m, 16 Aug 1973,Sagdstegui (F); Namora-Matara, A. 7755 (HUT, MO, NY); Huamachuco-Cajabamba, 2800 m, 16 Nov 1983,SagdsteguiA. 11144(HUT,NY). Local names. Peru.Cajamarca:shirac Solanumclivorumis probablymost closely related to S. oblongifoliumand may in fact be a geographical derivative of that species. It differs from S. oblongifoliumin its usuallydifoliate,geminatesympodial units, smaller, more membraneousflowers, and

FLORA NEOTROPICA

46

2. Solanum hypaleurotrichum Bitter, Repert. Spec. Nov. Regni Veg. 16: 100. 1916. Type. Colombia. Narifio:Pasto, Triana2243 (lectotype,W,heredesignated;isolectotypes, B [destroyed:F neg. 2664], NY). Figs. 19C, 22

800? )

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o .-

FIG. 21. Distributionof Solanum clivorum (open (solid circles). circle) and S. hypaleurotrichum

Shrubsor small trees, 2-8 m tall; young stems and leaves densely pubescentwith fawn (light beige) congested dendritictrichomesca. 1 mm long, the branches of the trichomesso closely packedthatthe structureis unclear;barkof older stems darkbrown,not glabrate. Sympodia plurifoliate. Leaves elliptic, widest at the middle,glabrousandshiningadaxially,densely pubescentabaxiallywithbeige congestedtrichomeslike those of the stems, these denser along the veins, often matted, leaf blades 3.5-15 cm long, 1.5-6 cm wide, with 6-8 pairsof main lateralveins, these impressedadaxially, the apex acute, the base acute;petiole 1.5-2.5 cm long. Inflorescencesterminal,laterlateral,2-7 cm long, 2-5 times branched,with 5-15 flowers, densely pubescent with beige congested trichomes (Christmastree-like)likethoseof thestemsandleaves;pedicelscars unevenly spaced 1-2 mm apart.Buds globose ca. 1/2 way included in the calyx tube. Pedicels at anthesis thick, 0.5-1 mm long, ca. 1 mm diam., densely pubescent with tree-liketrichomeslike those of the restof the inflorescence.Flowers with the calyx tube campanulate,constrictedatthebase,2-4 mmlong,thelobesdeltate, 1.5-3 mm long, with scatteredtree-liketrichomeslike those of the rest of the inflorescence; corolla white, fleshy, 1.6-2.4 cm diam.,lobed ca. 1/2 way to the base, the lobes planarat anthesis,the abaxial surfaces,margins and tips of the lobes densely papillose; anthers obovate, 3.5- mm wide, 2-2.5 mm wide at the apex, narroweratthebase,poricidalatthetips,theporeslengtheningto slits with age; freeportionof thefilaments1.52 mm long, the filamenttubeca. 0.5 mm long, glabrous; ovaryglabrous;style glabrous,heteromorphic,in shortstyled flowers ca. 4 mm long and included within the anthercone, in long-styled flowers 5-6 mm long, exsertedfromthe anthercone;stigma clavate,the surface minutelypapillose.Fruit a globose (wartyfide Cazalet & Pennington5511) greenberry,ca. 1 cm diam.,occasionallyapicallypointed;fruitingpedicelserect,woody, 1-2 cm long, 1-2 mm diam. at the base.Seeds reddishwithprominentincrassate brown(?), flattened-reniform margins,ca. 3 mm long, ca. 3 mm wide, the body of the seed flat, the margins minutely pitted. Chromosome number:n = 12 (voucher Knapp et al. 9085, 9094).

smaller berries on more elongate deflexed fruiting pedicels.The leaf andstemtrichomesofS. clivorumare generallysmallerandwith less elongatebranchesthan those of S. oblongifolium.In bothspecies, however,the The five projectionsfromthe trichomesaretransparent. filamenttubethatclosely investthe style in S. clivorum are occasionally present in S. oblongifolium. In S. oblongifolium,however, they are not as long and are not consistentwithin a given population.These projections are foundin all known collections ofS. clivorum. Two recent collections from Cutervo province (Sanchez Vega 4510, Stinchez Vega et al. 5960) are Distribution (Fig. 21). In dwarf cloud forest and unusualin theirvery large leaves, larger,waxier flowers, and glabrous corolla lobes. They may represent along paramoedges, at 2000-3500 m, Ecuador. merely a geographicalvariant,but could also be a difSelected specimens examined. ECUADOR. AZUAY: ferent species. No fruiting specimens have been col- Hacienda Yanasacha, 3000-3400 m, 24 Jul 1978, Boeke & Jaramillo 2530 (K, NY); Cuenca-Gir6n rd., Nudo lected from amongstthese populations.

47

TAXONOMIC TREATMENT

..

.

z?F ~ ?? ?r?:' '"???iiillij i,ii~ii '~ ?:l~i. ~~ i::li'?

Solanum Section Geminata (Solanaceae) (Flora Neotropica Monograph No. 84)

Cecropiaceae: Coussapoa and Pourouma, with an Introduction to the Family (Flora Neotropica Monograph No. 51)

Moreae, Artocarpeae, and Dorstenia (Moraceae): With Introductions to the Family and Ficus and With Additions and Corrections to Flora Neotropica Monograph 7(Flora Neotropica Mongraph No. 83)

Aiphanes (Flora Neotropica Monograph No. 70) Roystonea (FN No. 71) Euterpe, Prestoea, and Neonicholsonia (FN No. 72) Allagoptera (FN No. 73)

Flora Neotropica. : the Actinomorphic-flowered New World Lecythidaceae

Solanaceae fig

84

Flora

84

Lecythidaceae - Part I. The Actinomorphic-flowered New World Lecythidaceae (Asteranthos, Gustavia, Grias, Allantoma, & Cariniana) (Flora Neotropica Monograph No. 21(I))

EUROSAM '84

Приключения-84

SM.84

Flora nordica

flora lapponica

2001 (84)

Flora Segunda (Flora Segunda of Crackpot Hall)

Colorado Flora

Флора Западной Сибири П. Крылова. Solanaceae -- Dipsacaceae

SF-Stories 84 v3

بحار الأنوار - الجزء 84

Хоккей 84-85. Уфа

Пригоди. Подорожі. Фантастика - 84

Collected Poems, 1948-84

Sea-Section

Section 8

Section 8

Section 8

Section 8

Section 8

Section 8

Solanum Section Geminata (Solanaceae) (Flora Neotropica Monograph No. 84)

Cecropiaceae: Coussapoa and Pourouma, with an Introduction to the Family (Flora Neotropica Monograph No. 51)

Moreae, Artocarpeae, and Dorstenia (Moraceae): With Introductions to the Family and Ficus and With Additions and Corrections to Flora Neotropica Monograph 7(Flora Neotropica Mongraph No. 83)

Aiphanes (Flora Neotropica Monograph No. 70) Roystonea (FN No. 71) Euterpe, Prestoea, and Neonicholsonia (FN No. 72) Allagoptera (FN No. 73)

Flora Neotropica. : the Actinomorphic-flowered New World Lecythidaceae

Solanaceae fig

84

Flora

84

Lecythidaceae - Part I. The Actinomorphic-flowered New World Lecythidaceae (Asteranthos, Gustavia, Grias, Allantoma, & Cariniana) (Flora Neotropica Monograph No. 21(I))

EUROSAM '84

Приключения-84

SM.84

Flora nordica

flora lapponica

2001 (84)

Flora Segunda (Flora Segunda of Crackpot Hall)

Colorado Flora

Флора Западной Сибири П. Крылова. Solanaceae -- Dipsacaceae

SF-Stories 84 v3

بحار الأنوار - الجزء 84

Хоккей 84-85. Уфа

Пригоди. Подорожі. Фантастика - 84

Collected Poems, 1948-84

Sea-Section

Section 8

Section 8

Section 8

Section 8

Section 8

Section 8

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