Glabrous (calyx-tips microscopically pubescent). Stem 4–20 ft. high (Mann). Leaves up to 6 by 2 in., acuminate at either end, cystoliths many prominent; petiole 1/2–1 1/2 in. long. Spikes terminal, elongating in fruit up to 3 in., 4–10-flowered, lower flowers solitary, opposite, 1/4– 1/2 in. from the succeeding pair; bract 3/4–1 in. long, elliptic, deciduous; bracteoles hardly 1/4 in. long, narrow-oblong. Calyx-lobes 5, 3/4 in. long, nearly equal, linear-lanceolate; the 3 posticous sometimes connate even in fruit 1/3 their length, sometimes free even in the bud nearly to their base. Corolla 2 in. long, upper 2/3 of the tube much inflated, 1/2– 2/3 in. in diam., curved; lobes 1/2 in., round, violet-purple. Filaments glabrous, with glands near the top; pollen globose, echinate. Ovary and style glabrous; style-branches one obsolete, one broad ovate-oblong. Capsule 3/4 by 1/8– 1/10 in., subcylindric, about 16-seeded, seed-bearing from the base; seeds 1/16 in. in diam.
