Tuber depressed-hemispherical, 3–5 in. in diam. Stems 2–2 1/2 ft. high, erect or twining, puberulous. Leaves in 5–6 distant pairs on each stem; petiole 2–3 1/2 lin. long; blade 1–1 1/2 in. long, 5–10 lin. broad, obovate-oblong, very obtuse, rounded or subcuneate at the base, softly velvety on both sides, whitish beneath. Flowers in dense axillary subglobose sessile many-flowered clusters; pedicels about 1 lin. long, tomentose. Sepals 1 lin. long, 3/4– 5/6 lin. broad, broadly ovate, obtuse, tomentose. Corolla-tube about 1 lin. long; lobes oblong, obtuse, 2–2 1/4 lin. long, 1 1/4–1 1/3 lin. broad, glabrous on both sides. Coronal-lobes arising from the base of the staminal filaments, trifid to the base; side teeth or lobes 1/2 lin. long; middle lobe 1 3/4–2 lin. long, nearly 1/2 lin. broad at the base, flat, subulate-attenuate. Filaments of the stamens 1/2 lin. long, linear-oblong, shortly dilated at the base; anthers ovate, with short obtuse appendages, connivent.