Annuals or biennials; (glaucous); usually glabrous, (sometimes pedicels pubescent). Stems often branched distally, (2.3-) 4.5-12 dm. Basal leaves not rosulate; long-petiolate; blade oblanceolate to spatulate, 5-25 cm, margins lyrately lobed to irregularly dentate. Cauline leaves: blade oblong to ovate, 3-15 cm × 15-80 mm (smaller distally as bracts), base auriculate to amplexicaul, margins entire or shallowly dentate. Racemes bracteate throughout, (proximalmost bracts leaflike, distalmost much reduced). Fruiting pedicels divaricate-ascending, 7-19 mm, (glabrous or puberulent). Flowers: calyx campanulate; sepals (ascending to suberect), 8-12 mm, (not saccate basally), not keeled, (inner pair apiculate); petals purplish, 14-19 mm, blade 7-12 × 5-7 mm, margins not crisped, claw 6-8 mm, (slender), much narrower than blade; stamens tetradynamous; filaments: median pairs (distinct), 6-8 mm, lateral pair 4-6 mm; anthers (all) fertile, 4-6 mm; gynophore 1-2 mm. Fruits divaricate ascending, smooth, straight, flattened, 8-14.5 cm × 2.5-4 mm; valves each with prominent midvein; replum straight; ovules 48-80 per ovary; style 1-3.5 mm; stigma 2-lobed. Seeds oblong, 3-4 × 2-3 mm; wing 0.5-0.7 mm wide at apex, continuous.

Flowering Apr-Jun. Openings in oak-juniper woodlands, shallow, well-drained, gravelly clay-loam areas derived from limestone, dry rock hills, bluffs; of conservation concern; Tex.

Streptanthus bracteatus is restricted to Austin, Bandera, Blanco, Medina, Real, and Travis counties. It is in the Center for Plant Conservation´s National Collection of Endangered Plants.