Gesneriad Reference
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SMITHSONIAN CONTRIBUTIzONS TO BOTANY NUMBER 29 A Study of the Tribe Gesnerieae, with a Revision of Gesneria (Gesneriaceae: Gesnerioideae) Laurence E. Skog SMITHSONIAN INSTITUTION PRESS City of Washington 1976 ABSTRACT Skog, Laurence E. A Study of the Tribe Gesnerieae, with a Revision of Gesneria (Gesneriaceae: Gesnerioideae). Smithsonian Contributions to Botany, number 29, 182 pages, 86 figures, 9 tables, 1976.-A study is made of the tribe Gesnerieae of the family Gesneriaceae from the West Indies, giving information on history, anatomy and morphology, pollination and dispersal, and hybridization in the tribe. The tribe comprises 67 species in 3 genera: Rhytidophyllztm, Gesneria, and Pheidonocarpa. The last genus is described as new, with a new species com- bination, Pheidonocarpa corymbosa (Swartz) L. Skog, and 2 subspecies. A revi- sion of Gesneria Linnaeus is presented based on field and herbarium studies. Gesneria is divided into 9 sections, 46 species (a new species, Gesneria onycho- calyx L. Skog, is described), 12 subspecies, and 11 varieties. The taxonomic portion includes keys, synonymies, descriptions, typifications, distributions, and ecology, as well as distribution maps and illustrations of the taxa. Also enum- erated in Appendix 1 are many species names once included in Gesnera or Gesneria, but which have been transferred to other genera. Two new combina- tions are made in this portion of the text: Rhytidophyllum cumanense (Han- stein) L. Skog and Rhytidophyllum onacaense (Rusby) L. Skog. OFFICIALPUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution’s annual report, Smithsonian Year. SI PRESSNUMBER 6053. SERIESCOYER DFSIGN: Leaf clearing from the Katsura tree Cercidifihyllum japonicum Siebold and Zuccarini. Library of Congress Cataloging in Publication Data Skog, Laurence E. 1943- A study of the tribe Gesnerieae, rrith a revision of Gesneria (Gesneriaceae: Gesnerioideae) (Smithsonian contributions to Botany ; no. 29) Bibliography: p. Includes index. Supt. of Docs. no.: SI 1.29:29 1. Gesneria. 2. Rhytidophyllum. 3. Pheidonocarpa. 4. Botany-Jt’est Indies. I. Title. 11. Title: Gesnerieae, with a rekision of Gesneria (Gesneriaceae: Gesnerioideae). 111. Series: Smithsonian Institution. Smithsonian contributions to Botany : no. 29. QKlS2747 no. 29 [QK495.G4] 581’.08s [583’.81] 75-61934 Contents Page Introduction ........................... ........................ 1 Historical Review ..... ............................. 2 Morphology and Anatomy ................... .............. 6 Pollination and Seed Dispersal ...................................... 26 Hybridization and Cytology ................................ 33 Systematic Treatment ............................................. 36 Tribe GESNERIEAE................................................. 36 Key to the Genera in Tribe Gesnerieae ........................ 39 Pheidonocarpa .......................... .............. 40 Gesneria ...................................................... 43 Key to the Sections of Gesneria ................................. 45 Section 1. Pentarhaphia .............................. .. 46 Key to the Species of Section Pentarhaphia ....................... 46 Section 2 . Stenochonanthe ... ...................... ....... 80 Section 3 . Lachnoblaste .................... .............. 85 Section 4 . Myrmekianthe ................ ............... 86 Section 5. Gesneria ............................................ 90 Key to the Species of Section Gesneria .................... 91 Section 6. Physcophyllon ....................................... 100 Key to the Species of Section Physcophyllon ...................... 101 Section 7. Dittanthera ............... ....................... 121 Key to the Species of Section Dittanthera ......... 123 Section 8. Duchartrea .......................... 137 Section 9 . Chorisanthera ..... .............................. 145 Key to the Species of Section C sun thera ...................... 145 Appendix 1: Excluded Species ...................................... 158 Appendix 2: Numerical List of Taxa ................................ 165 Appendix 3: List of Exsiccatae ...................................... 166 Literature Cited . .............................................. 171 Index ............................................................ 176 ... 111 A Study of the Tribe Gesnerieae, with a Revision of Gesneria (Gesneriaceae: Gesnerioideae) Laurence E. Skog Introduction Gesnerieae has not been attempted since the treatments by Hanstein from 1854 to 1865. Because the Scrophu- The Gesneriaceae, a member of exploration of the American tropics in the last one of Cronquist lariales in the classification system hundred years has revealed many species new to (1968), are found in tropical and subtropical science, a study of this group of flowering plants is regions of the world, but rarely occur wild in long overdue. In the study of the systematics of temperate zones. The family is composed of about Gesnerieae, perhaps the most difficult problem is 120 genera and about 1800 species; two subfami- generic delimitation, a problem found in other lies are recognized, separated by Burtt (1962) on groups in tlic American Gesneriaceae (Hurtt, the characters of seedlings into the anisocotylous 1956; Moore and Lee, 1968). The factors above Cyrtandroideae, primarily Old World, and the and those following led to the choice of the Ges- isocotylous Gesnerioideae in the New World. The nerieae as a taxon for investigation: (1) the pos- latter subfamily has been tentatively divided into sibility of unusual pollination mechanisms in the five tribes by Wiehler (1970) using characters of tribe: and (2) the availability of material of many epidermal cell sinuation, node vasculature, shape species of the genera included in the Gesnerieae of the vascular crescent in the petiole, and leaf among the living collections of Gesneriaceae at arrangement. The tribe Gesnerieae, one of the Cornell University and elsewhere. five tribes maintained by Wiehler in the Gesneri- In the study of the tribe Gesnerieac and the oideae, is apparently restricted geographically to genus Gesneria presented here, three avenues of the West Indies and a few localities in northern research were explored: (1) a morphological and South America. It is restricted morphologically and anatomical approach to discover or elucidate anatomically by the occurrence of alternate leaves floral and vegetative characters, using living in most of the members of the tribe, by having the material where possible to supplement herbarium vascular trace of the petiole invaginated or cylin- specimens; (2) a comparison of chromosome drical (Wiehler, 1970), by the fruticose or analysis with the rcsults of hybridization to suggest arborescent habit, an inferior or subinferior ovary, the genetic bases for morphological characters; and by having a chromosome number of n = 7, and (3) field studies and investigation of possible 14, or 28. pollination mechanisms, which may reveal the The taxonomy of all known members of the interaction of the species of the Gesnerieae with the environment and how the interaction influ- Laurence E. Skog, Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, ences speciation and evolution within the group. D. C. 20560. ACKNoWLEDGMEwrS.-A substantial part of the 1 2 SMITHSONIAN CONTRIBUTIONS TO BOTANY work presented here was undertaken at Cornell drawings and descriptions were never published in University and was submitted as a thesis in partial full, although at least three sets of Plumier’s draw- fulfillment for the degree of Doctor of Philosophy ings were distributed after his death. One set was (Skog, 1972~). made in 1733 by Claude Aubriet for Herman I greatly appreciate the advice and assistance of Boerhaave. After the death of Boerhaave, the the members of my special committee at Cornell Aubriet copies went to Johannes Burman, who University: H. E. Moore, Jr., Chairman, for his later used the drawings in preparation of Plumier’s special knowledge of the Gesneriaceae; H. P. Plantarum Americanaruin Fasciculus Primus (-Deci- Banks, for help in problems of morphology and mus), which he edited (1755-1760). Plumier’s anatomy: and G. C. Eickwort, for advice on pol- original manuscript and 5081 drawings are now at lination mechanisms. the Bibliotheque Centrale of the Museum Na- Financial assistance from three sources permit- tional d’Histoire Naturelle at Paris, whence copies ted research in new areas: Horticulture Inter- were obtained to clarify the descriptions of change Fellowship of the Garden Club of America, Linnaeus. The Aubriet copies are now in the the English-Speaking Union, and Fison’s Horti- University Library at Groningen, Netherlands, culture, Ltd., allowed research at the Royal and other sets of copies are in the Herbarium Botanic Garden, Edinburgh, during 1968-1 969; Library of the Royal Botanic Gardens, Kew, and National Science Foundation Grants GB-6277 and at the Department of Botany, British Museum GB-8766, to H. E. Moore, Jr., principal investigator, (Natural History), London. Gesneria humilis, G. provided support from 1969 to 1972 and permitted tomentosa (= Rhytidophyllum tomentosum (Lin- a collecting trip to the West Indies in 1970; and a naeus) Martius [in part]), and Cranz’olaria gift from the American Gloxinia and Gesneriad fruticosa ( = Gesneria {ruticosa (Linnaeus) 0. Society to the L. H. Bailey Hortorium supported Kuntze), described by Linnaeus in 1753,