Systematics of the neotropical plant genera Alloplectus and Glossoloma (Gesneriaceae: Episcieae).

摘要

The neotropical plant tribe Episcieae is one of the least understood in its family, with 22 genera and over 700 species, or roughly 21% of all Gesneriaceae. Most traditionally recognized genera in Episcieae are known to either not be monophyletic or have not been adequately represented in previous analyses. This dissertation presents phylogenetic analyses utilizing two molecular datasets [the internal transcribed spacer region of 18S-26S nuclear ribosomal DNA (ITS) and the chloroplast trnH-psbA intergenic spacer for 155 species] and morphology (103 characters for 119 species) combined in a total evidence analysis. All traditionally recognized genera of Episcieae are represented, except for the monotypic genus Lampadaria.; Three independent origins of resupinate flowers are reported for Glossoloma, Nematanthus, and Crantzia. Strongly supported clades are reported with centers of diversity in southeastern Brazil (Nematanthus, Codonanthe, Codonanthopsis, and Paradrymonia anisophyla); northern South America (Alloplectus, Drymonia, Columnea, Neomortonia); Central America (Alsobia, Oerstedina, Rufododorsia, Cobonanthus); and two clades with diversity in the Guiana shield [(Paradrymonia, Nautilocalyx, Chrysothemis) and (Lembocarpus, Cremersia, Rhoogeton)].; Monographic revisions for Alloplectus Martius and Glossoloma Hanstein are presented. Alloplectus comprises five species and extends from Costa Rica to the Andes of Colombia, Ecuador, and Peru. Plants of Alloplectus are obligate epiphytes with tubular non-resupinate flowers. Glossoloma comprises 27 species and extends from southern Mexico to Panama, northwestern South America, and south to Bolivia. Plants of Glossoloma are unbranched terrestrial subshrubs and occasionally facultative epiphytes. Nearly all species of Glossoloma have resupinate flowers with laterally compressed tubular corollas that are apically pouched.; The data presented here will further the study of Gesneriaceae and contribute the first comprehensive phylogeny of the tribe Episcieae. Significant morphological synapomorphies that are reported as a result from this study are tardily dehiscent endocarps and resupinate flowers. Ten species new to science were discovered and described. In addition, 21 new combinations, two lectotypifications, and four neotypifications are presented. These studies and the availability of this new information will facilitate investigations on pollination biology, biogeography, and biodiversity of neotropical forests.