Usually 60-90 cm high. Branchlets villous. Leaves mostly 4-6 mm long, erect-spreading, ascending or appressed, at first shortly imbricate, ovate, oblong-lanceolate or ovate with the lower part narrowing to the base, acute, convex and villous beneath where ultimately glabrous or retaining hairs at the margins, concave and glabrous above. Flowers overtopping the leaves, crowded in ovate, rotund or spherical heads usually 1-1-5 cm long. Bracteoles linear, acuminate, villous on the back, concave on the inner face, reaching to the middle of the corolla. Calyx-tube obconic, adhering throughout to the ovary or with a cup-shaped upper part: calyx-lobes 4-8 mm long, linear or lanceolate, acuminate, flat, villous on the back. Corolla 0-8-1-1 cm long: petals connate for about 1/3 of their length in a narrowly cyathiform tube; the free part ovate-lanceolate, acute, white. Stamens as long as the tube: filaments adnate to the tube: anthers 1-5 mm long: thecae free in the lower half, pubescent on the dorsal surface. Ovary 1/2-1/3 inferior, globose and pubescent in the upper part, with two 1-8-ovulate chambers (the number greatest in the lower flowers): styles firmly connate throughout or shortly free, reaching to the anthers.
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Like B. pentandra but flowers in terminal and lateral spikes, white, and styles entirely united.