Systematics of Columnea Section Pentadenia and Section Stygnanthe (Gesneriaceae)

The 27 species of Columnea (Gesneriaceae) here described are assigned to sections Pentadenia and Stygnanthe. They are herbaceous perennials, occurring from southern Mexico to Bolivia from near sea level to 3800 m. In addition to morphology, geographic distribution, breeding systems, and phylogeny are discussed. The taxonomy is based on cladistic analyses of morphological diversity and chloroplast DNA restriction site variation (details of the analyses are published elsewhere). Section Pentadenia, previously monotypic, now comprises 9 species of suffrutescent robust herbs with isophyllous to slightly anisophyllous leaves, long pedicels, and conspicuous, strongly ventricose corollas. Section Stygnanthe, also newly circumscribed, includes 18 species of creeping, pendent, or upright herbs with isophyllous to anisophyllous leaves, short pedicels, and generally small, inconspicuous, and only slightly ventricose corollas. Three new combinations are proposed in sect. Stygnanthe: Columnea antiocana, C. fritschii, and C. rileyi.