Like B. pentandra but leaves broadly ovate-elliptic, flowers pink, petals fused for two-thirds their length, styles 10-14 mm, longer than petal tube.
About 60 cm high, moderately and often virgately branched. Branchlets villous. Leaves mostly 1-1.3 cm long, erect-spreading, ovate (the upper often narrowly ovate), acute, sparsely villous beneath, flat or slightly concave and glabrous above, ciliate, becoming glabrous. Flowers in the axils of reduced leaves, crowded in globose or hemispheric inflorescences usually about 2 cm wide. Bracteoles about 9 mm long, linear-oblanceolate, acute, navicular, villous on the back, ciliate. Calyx-tube obconic: calyx-lobes 3-3.5 mm long, oblong-lanceolate, acute, villous on the back, ciliate. Corolla 1-2-1-3 cm long, glabrous: petals connate slightly less than 2/3 in a cylindric tube; the free part consisting of a cuneate-oblong claw widening into an ovate or obovate acute lamina. Stamens inserted at the mouth of the tube: filaments about 2-5 mm long: anthers about 2 mm long, narrowly sagittate. Ovary J inferior, bilocular, 8-12-ovulate, broadly elliptic in the superior portion: styles slender, free, reaching to well above the free part of the petals; stigmas minute.