Drymonia

Abstract: Episcieae is the most diverse tribe of Gesneriaceae, with 22 genera and over 700 species, or roughly 21% of all Gesneriaceae. The tribe is restricted to the Neotropics and is characterized by axillary flowers derived from a pair-flowered cyme inflorescence by reduction, a three-trace trilacunar node with split lateral bundles, superior ovaries, and with most members having a haploid chromosome number of n = 9 [n = 8 in Codonanthe and Nematanthus]. Most traditionally recognized genera in Episcieae are either known to be non-monophyletic or have not been represented adequately in phylogenetic analyses to test their monophyly. This paper presents phylogenetic analyses utilizing two molecular [the internal transcribed spacer region of 18S-26S nuclear ribosomal DNA (ITS) and the trnH-psbA intergenic spacer for 155 species] and one morphological (99 characters for 120 species) datasets, combined in a total evidence analysis. All traditionally recognized genera of Episcieae except for the monotypic genus Lampadaria are represented. Of the 21 sampled genera in Episcieae, 16 are represented by the generic type species. The genera Glossoloma and Crantzia are segregated from the genus Alloplectus as traditionally recognized. Other genera that are strongly supported as monophyletic include Alsobia, Columnea (with the inclusion of C. dielsii), Corytoplectus, and Episcia. Drymonia is weakly supported and is shown here to be morphologically diverse and in need of further evaluation. Evolution of fruit structure is examined in the context of the phylogenetic results presented here with two previously unreported features that are here referred to as capsules with tardily dehiscent and non-dehiscent endocarps. Three independent origins of resupinate flowers are inferred for Glossoloma, Nematanthus, and Crantzia. Strongly supported clades have centers of diversity in southeastern Brazil (Nematanthus, Codonanthe, Codonanthopsis, and Paradrymonia anisophylla), northern South America (Alloplectus, Drymonia, Columnea, Neomortonia), Central America (Alsobia, Oerstedina, Rufodorsia, Cobananthus), and two clades with diversity in the Guiana Shield [(Paradrymonia, Nautilocalyx, Chrysothemis) and (Lembocarpus, Cremersia, Rhoogeton)]. Neomortonia, a genus of three species, is poorly supported due to conflict among datasets.

Abstract: The neotropical members of Gesneriaceae are characterized by numerous characters that appear to be adaptations to life in the wet tropics. Among these are epiphytism, anisophylly, hummingbird- pollination, and bird-dispersal of seeds. Many of these characters have diversified to a broad extent in the single tribe Episcieae. This analysis investigates the phylogenetic relationships among genera of Episcieae and also examines the evolutionary origin of several characters found within this tribe such as fruit characters, epiphytism, chromosome numbers, and tubers. All genera of the tribe were included in the analysis except the Guyana endemic Rhoogeton and the Central American Oerstedina. Larger genera such as Columnea and Episcia were represented by several species with attempts to include members of the different sections of these genera. Columnea appears to be a monophyletic group but its relationship to Drymonia and Alloplectus is not resolved. The latter genera may need to be included in Columnea to make it strictly monophyletic. Neomortonia is polyphyletic with one species in the Columnea clade and another with Episcia.- The anomalous position of some Paradrymonia indicate a more thorough analysis of this genus is necessary to resolve phylogenetic relationships.

Abstract: A cladistic analysis of chloroplast DNA (cpDNA) restriction site variation was per- formed on Columnea (Gesneriaceae) sections Pentadenia and StVgnan,he. Two species of Alloplectus were included in the analyses and one of Drymonia was used as the outgroup. Restriction site variation was analyzed using Wagner parsimony and character state weighting that favors conver- gent losses over convergent gains. The large numbers of equally most parsimonious trees prevented examination of each tree independently. Thus, examination of phvlogenetic relationships was based on a strict consensus of all most parsimonious trees. The resulting phylogeny is largely congruent with recent classification schemes, although the positions of several species are not in accordance with traditional relationships. As a result of the cladistic analysis of the cpDNA restriction site variation, section Pentadenia is at least paraphyletic, and possibly polyphyletic with section Styg- nanthe. The lack of resolution among the several clades within section Stygnanthe does not provide evidence for or against monophyly of this section. Several clades are strongly supported with cpDNA data and provide insight into biogeography and origin of morphological adaptations.

Abstract: A cladistic analysis was performed on morphological data from seven of the nine species of Columnea section Pentadenia and sixteen of the eighteen species of section Stygnanthe (Gesneriaceae). A nested, global outgroup analysis was performed by including representatives of three other sections of Columnea and two species each of the closely related genera Alloplectus and Drymonia. Twenty characters were scored as binary, and thirteen were scored as multi-state. All characters scored were qualitative. Because of the high levels of homoplasy in the Gesneriaceae, simple characters were not found to be useful and more complex characters comprising several simple characters were necessary to provide resolution. The data were analyzed using Wagner parsimony, resulting in eight most parsimonious trees. In general, the phylogeny was congruent with current classification schemes and phylogenies derived from molecular data and combined molecular and morphological data. However, several phylogenetic relationships that result from the analysis of morphological data are suspect based on other data. The monophyly of Alloplectus is not supported solely with morphological data, although other data support its monophyly. In- ferences regarding the biogeographic history and evolution of Columnea sections Pentadenia and Stygnanthe indicate a southern Andean origin for the genus Columnea with a subsequent migration and radiation northward.