Passiflora brachyantha (Passifloraceae), a New Species from the Andes of Southern Ecuador

Abstract

A new species of Passifora subg. Tacsonia is described from the Andes of southern Ecuador. Passiflora brachyantha is placed in section Bracteogama, where it most closely resembles another short-flowered species, P. glaberrima, which is endemic to Peru. Members of Passifora subg. Tacsonia (A. L. Juss.) Triana & Planchon, are tendriled lianas confined to high Andean habitats, distributed from the Cordillera de Merida in northwestern Venezuela to Bolivia. One cultivated species, Passiflora pinnatistipula Cav., is found in mesic sites in the Andes of Chile. The plants are characterized by long-tubed, highly colored, hummingbird-visited flowers, and the geographical distribution of the plants coincides with that of Ensifera ensifera, the sword-billed hummingbird (Escobar, 1980, 1989b; Schauensee, 1982). Hypanthium length in the subgenus varies, however, and falls mainly into two groups: (1) longtubed species probably pollinated by Ensifera ensifera, as is the most widespread species, Passifora mixta L. f. (Snow & Snow, 1980), and (2) shortertubed species presumably pollinated by shorter-billed hummingbirds. There are few species of intermediate hypanthium length (Escobar, 1980). Since all of the subgenera of Passifiora that are confined to the high Andes produce flowers adapted for hummingbird pollination (Escobar, 1989b, and unpublished data), it is likely that the short-tubed taxa, which are most common in southern Ecuador and northern Peru, have speciated in response to the selective pressures exerted by their pollinators. Section Bracteogama (DC.) L. Escobar comprises 14 of the 47 species placed by Escobar in subgenus Tacsonia (Escobar, 1980, 1987, 1988, 1989a) and has its center of diversity in the moist montane forests of southern Ecuador and the eastern Andean slopes of northern Peru around the Huacabamba depression. The members of the section are recognized by the presence of large, coriaceous, mostly connate bracts that enclose and presumably protect the bud during development (Escobar, 1980; Harms, 1925). Both long-flowered and short-flowNOVON 2: 198-200. 1992. ered species occur in this section. The new species described here is another short-flowered member of section Bracteogama. Passiflora brachyantha L. Escobar, sp. nov. TYPE: Ecuador. Loja: 8 km W of Loja on road to Catacocha, 7,400 ft., 30 Jan. 1979 (fl, fr), R. M. King & F. Almeda 7887 (holotype, US). Figure 1. Differt a Passiflora glaberrima (A. L. Juss.) Poiret caulibus foliis bracteisque pubescentibus, foliis majoribus apicibus acuminatis, et floribus roseis. Lianas with stout tendrils, pubescent on stems, petioles, peduncles, bracts, and abaxial surface of leaves and stipules, with straight to wavy, transparent trichomes to 0.5 mm long. Stems angulate, striate. Leaf blades 3-lobed, 3.5-7.3 cm long, 7.811.0 cm wide, parted ca. 34 their length into 3 elliptic segments, acuminate at apex of lobes, shallowly cordate at base, glandular-serrate at margins, coriaceous; lateral segments 2.2-5.5 cm long, 1.63.4 cm wide, divergent from mid-segments ca. 90?; mid-segments 3.5-7.3 cm long, 1.6-3.3 cm wide; petioles 1.2-2.7 cm long, with 3-5 subspherical nectaries 0.7-1.2 mm long, 0.8-1.0 mm wide, scatt red on upper half of adaxial surface; stipules reniform, concave, 1.2-1.5 cm long, ca. 6 mm wide, attenuate at apex, oblique at base, shallowly glandular-serrulate at margins, coriaceous, glabrous on adaxial surface. Peduncles slender, 2.7-3.4 cm long, bearing pendent flowers; bracts oblong, connate ca. 34 their length from base, forming an ampliate tube at base of hypanthium, each bract 3.1-3.5 cm long, 1.0-1.1 cm wide, acuminate at apex. Flowers 6.46.8 cm long, ca. 3.5 cm wide, bright pink; hypanthium 3.9-4.0 cm long, 0.4-0.6 cm wide (pressed), dilated at base, pubescent on outer surface with straight, transparent trichomes ca. 0.3 mm long; sepals oblong, ca. 2 cm long, ca. 0.6 cm wide, pubescent with subterminal aristae ca. 1 mm long on abaxial surface; petals subequal to sepals; corona tuberculate, ca. 0.3 mm long; ovary ellipsoidal, pubescent with fine, straight trichomes ca. 0.1 mm This content downloaded from 157.55.39.181 on Thu, 29 Sep 2016 06:16:24 UTC All use subject to http://about.jstor.org/terms Volume 2, Number 3 1992 199 Escobar Passiflora brachyantha