Stems usually branched for most of length (occasionally only distally). Bracts on distal portions of inflorescences linear to narrowly deltate, mostly 2–6 mm (seldom less than 2 mm). Flowers: corolla tube (7–)8–12(–13) mm, moderately to strongly constricted just below apex, often in distinct narrow band (most visible just before anthesis); stigma apiculate with 2 small lobes. Follicles moniliform, strongly constricted between seeds. Seeds light reddish brown to pale brown, fusiform with acute to rounded-acute or flat-truncate (rarely diagonally truncate) ends, mostly smooth except at ends and with a prominent longitudinal groove.

Species 2 (2 in the flora): sw, sc United States, n Mexico.

Within subg. Articularia, as many as four species, one with two varieties, have been recognized. The most recent revision (S. P. McLaughlin 1982) recognized only one species with two varieties.