An erect annual herb, 6–18 in. high, almost glabrous or more or less covered with short stiff hairs, usually very scabrid; stem simple or freely branched; branches erect-spreading. Leaves mostly alternate, linear to linear-lanceolate, 1/2–2 in. long, 3/4–2 lin. broad, rather acute, entire or few-toothed. Flowers axillary, solitary, alternate, forming long lax terminal spikes; lower bracts leaf-like, the upper linear to subulate, 2–4 lin. long, shortly and finely pubescent; bracteoles linear, 1 1/4–2 lin. long, otherwise as the bracts. Calyx tubular, 5–5 1/2 lin. long, prominently 15-ribbed, 5-toothed, hispidly pubescent; teeth lanceolate, slightly unequal, 1 1/2–1 3/4 lin. long, elongating in the fruiting stage, acute. Corolla rather densely white-pilose on the upper part of the tube and on the outside of the limb; tube about 1/2 in. long, abruptly curved about 1/3 in. from the base and inflated at the curve; upper lip broadly obovate, emarginate or truncate, 1 1/2–2 lin. long, 2–2 1/2 lin. broad; lobes of the lower lip narrowly obovate to obovate-oblong, 2 1/2–3 lin. long, 1 1/4–1 3/4 lin. broad, obtuse. Capsule ovoid, 1/4 in. long, 1 3/4 lin. broad, apiculate; valves recurved at the apex after dehiscence.
