Monographs Details: Banisteriopsis nutans (Poepp. ex Nied.) B.Gates
Authority: Gates, Bronwen. 1982. Banisteriopsis, Diplopterys (Malpighiaceae). Fl. Neotrop. Monogr. 30: 1-238. (Published by NYBG Press)
Synonyms:Banisteria nutans Poepp. ex Nied., Banisteriopsis panamensis Cuatrec. & Croat
Description:Species Description - Liana, branches appressed-sericeous, soon glabrate. Stipules triangular up to 1 mm long, sparsely sericeous. Leaves falcate with the petiole (3-)5-9 mm long, sparsely appressed-sericeous to glabrate, eglandular, the lamina 4.2-12.7(-16.2) cm long, 1.9-5.7(-7.3) cm wide, elliptic or rarely obovate, cuneate at the base, short- to long-acuminate at the apex, with the margin plane to slightly revolute and bearing minute glands, glabrous adaxially, sparsely appressed-sericeous to glabrate abaxially, the hairs 0.2-0.6 mm long, plane adaxially, with the reticulation prominulous to prominent abaxially. Inflorescence axillary, 1-3 branches per leaf axil, each branch usually bearing a single 4-flowered umbel, rarely a cyme of 3 umbels, appressed-sericeous, the hairs brown to golden; bracts and bracteoles 1.0-1.6 mm long, broadly triangular, appressed-sericeous, involucrate, persistent; pedicels sessile, 12—22(—25) mm long, 0.6-0.8 mm in diameter, appressed-sericeous, the hairs brown with the trabecula 0.3-0.5 mm long. Sepals 2.0-2.8 mm long, the anterior sepal 1.2-2.2 mm wide, the 4 lateral sepals 2.0-2.8 mm wide at the base, narrower at the apex, broadly ovate, rounded at the apex, appressed-sericeous abaxially, glabrous adaxially, the 4 lateral sepals Eglandular, projecting 0.2-0.8 mm beyond the glands, the glands 2.0-3.8 mm long, and 1.2-2.0 mm wide. Petals yellow, externally sericeous, lacerate to fimbriate, the 4 lateral petals reflexed between the sepals, broadly elliptic, the claw 1.0-2.0 mm long, the limb of the antero-lateral petals 8.5-11.0 mm long and 7.5-9.0 mm wide, concave, the limb of the postero-lateral petals 6.0-8.0 mm long and 5.0-7.0 mm wide, plane, the posterior petal with the claw erect, 3.0-4.0 mm long, up to 1.0 mm wide distally, constricted at the apex, the limb 5.0-6.5 mm long and 3.5-5.0 mm wide, obovate, plane, the basal laciniae sometimes gland-tipped. Stamens with the filaments 1.0-4.0 mm long, that opposite the anterior sepal longest, that opposite the posterior petal shortest, those opposite the sepals usually longer than those opposite the petals, or those opposite the postero-lateral petals as long as or longer than those opposite the antero-lateral sepals, those of the 3 posterior stamens sometimes inflexed between the posterior styles, those of the 3 anterior stamens connate basally, those of the other 7 stamens connate for up to half their length; anthers with the locules 0.9-1.8 mm long, sparsely hairy, the connectives of the stamens opposite the sepals 0.9-1.6 mm long, 0.7-1.0 mm wide, 0.6-0.8 mm deep, obovate or elliptic, those opposite the petals 0.8-1.2 mm long, 0.4-0.8 mm wide and 0.3-0.6 mm deep, narrowly oblong or narrowly elliptic. Ovary 1.0-1.4 mm tall, densely hairy, the styles subequal, 2.2-2.6 mm long, 0.2-0.3 mm in diameter, the anterior style sometimes a little stouter and longer than the posterior styles, diverging, glabrous or basally hairy, stigmas capitate. Fruit with short broad carpophore, the nut 6-8 mm tall and 5-7 mm long, with a series of parallel ridges or crests radiating from the areole laterally, tomento-sericeous to glabrate, the hairs sessile with the trabecula flexuous and 0.2-0.4 mm long, the wing 30-47 mm long, 10-19 mm wide, with the upper and lower margins more or less parallel, appressed-sericeous to glabrate, the hairs sessile with the trabecula 0.20.4 mm long, bearing an appendage on the upper edge at the base 2.5 mm tall and 4-7 mm along the base.

Discussion:Collected in flower in February, April, May, August, and November, and in fruit in May, August and September.

This species differs from Banisteriopsis lucida in its larger flowers with large calyx glands, its stout, subequal, diverging styles, and its shorter, stouter fruit wing which is not constricted at the base. There is considerable variation in the leaves and fruits shown by the specimens I have included in this taxon. The specimens from Venezuela differ from the Peruvian specimens in their smaller, more coriaceous leaves with short petioles (3-5 mm) but in flower and fruit are very similar; the Bolivian specimens are unusual in their very large calyx glands, large coriaceous leaves, and subequal, erect stamen filaments, and in this last character they approach B. nigrescens. The two collections from Panama are like the Venezuelan specimens in leaf size and shape, but the fruit nut is alulate, with the winglets developing from ridges radiating from the areole but superficially appearing parallel to the areole. This development of the lateral crests on the fruit into winglets is also found in B. lucida and I have not considered it to be taxonomically significant. With the winglets appearing parallel to the areole, the Panamanian specimens resemble B. platyptera and these two species are almost indistinguishable in flower, although the mode of development of the lateral wings is apparent early in fruit and makes their separation even in young fruit simple.
Distribution:Panama Central America| Venezuela South America| Lara Venezuela South America| Peru South America| Huánuco Peru South America| Cusco Peru South America| Bolivia South America|