A monographic study of sections Pentadenia and Stygnanthe of Columnea (Gesneriaceae) has revealed four species new to science and two new combinations. These species are described here and include C. atahualpae and C. hypocyrtantha of section Pentadenia, and C. manabiana, C. suffruticosa, C. ultraviolacea, and C. xiphoidea of section Stygnanthe. Columnea L. is a genus of neotropical plants distributed from southern Mexico to Bolivia comprising approximately 200 species. Species of Columnea are readily distinguished by their long tubular corollas that are either bilabiate or ventricose, and the fleshy, indehiscent, berry fruits. The majority of species are epiphytic, although several can be terrestrial as well. A revision of the species of Columnea in Ecuador conducted by Kvist & Skog (1993) and a treatment of the Gesneriaceae of Panama by Skog (1979) are the only recent taxonomic treatments of the genus. Wiehler (1973, 1983) divided the genus into four segregate genera and described a fifth genus allied to the Columnea complex. These five genera were combined back into the single genus Columnea by Kvist & Skog (1993). The four new species described here are the result of a monographic study of two of the smaller sections of Columnea, sections Pentadenia and Stygnanthe (Smith, 1991). The two new combinations result from a recent publication of new species of Gesneriaceae (Wiehler, 1992). Columnea (section Pentadenia) atahualpae J. F. Smith & L. Skog, sp. nov. TYPE: Ecuador. El Oro: forest along trail from Sambotambo, following headwaters of Rio Moro Moro S to Buenaventura, at and along highway to Portovelo, 29 Aug. 1943, Steyermark 54228 (holotype, F). Figure 1. NOVON 3: 186-197. 1993. Differt a Columnea nervosa (Klotzsch ex Oersted) Hanstein foliis ellipticis vel obovatis bracteis magnis corollis brevis (3.0-3.3 cm longis) marginibus integris trichomatibus appressis aureis. Suffrutescent terrestrial (or possibly epiphytic) herbs with erect stems to 1 m tall (Fig. 1A). Stems 8-12 mm diam., tawny brown, apex appressed pubescent with golden yellow uniseriate trichomes, lower stem smooth and glabrous. Internodes 2.5-9.0 cm long, leaf scars slightly raised from the slightly swollen nodes. Leaves opposite, equal to subequal, blades obovate to elliptic, 9.2-22.5 x 3.7-7.8 cm, apex acute, base cuneate-oblique, adaxially green, strigose-appressed pilose with single-celled, transparent, and uniseriate golden yellow trichomes, abaxially silvery green-maroon, vestiture similar to adaxial surface but sparser, pubescence of veins abaxially sericeous, margin entire to slightly undulate (Fig. 1A, B). Petioles 1.0-3.2 cm, appressed pilose with uniseriate golden yellow trichomes. Inflorescences 1-7 flowers in axils of either leaf pair (Fig. 1A), floral bracts 1-2 of unequal size, lanceolate-ovate, 8-22 x 1.5-16 mm, apex acuminate, slightly constricted at base, reddish, appressed pilose with uniseriate golden yellow trichomes, margin entire. Pedicels 1.3-1.9 cm, erect in leaf axil, appressed pilose with uniseriate golden yellow trichomes, 1-several glands present on pedicel, purplish, ca. 0.4 mm long. Calyx clasping corolla at base but more open toward apex of lobes, lobes lanceolate-subulate, equal in size, 1.5-2.7 x 0.30.5 cm, apex long acuminate, green with red tips to purple, margins serrulate-subulate, 3-5 teeth per side, mostly basal, exterior sericeous with uniseriate golden yellow trichomes, interior surface similar but trichomes sparser (Fig. 1C). Corolla pale yellow, tubular, gibbous at base, slightly ventricose, 3.03.3 cm long, 3.0 mm wide at base, 5-8 mm at widest point, 4-5.5 mm before limb, exterior apThis content downloaded from 157.55.39.151 on Fri, 29 Jul 2016 04:57:25 UTC All use subject to http://about.jstor.org/terms Volume 3, Number 2 1993 Smith & Skog Columnea