20. Streptanthus hispidus A. Gray, Proc. Calif. Acad. Sci. 3: 101. 1864; Euclisia hispida (A. Gray) Greene, Leafl. Bot. Observ. Crit. 1: 83. 1904. TYPE: United States, California, Contra Costa Co., dry summit, Mt. Diablo, 1860–1862, W. H. Brewer 1098 (holotype, GH!).
Herbs, annual, densely hirsute-hispid throughout with simple trichomes to 1.4 mm. Stems 0.3–3 dm, simple or branched about base. Basal leaves not rosulate, shortly petiolate, obovate, 1–5 cm, coarsely to shallowly dentate; middle cauline leaves obovate to oblong, 0.7–6 x 0.2–2.5 cm, sessile, cuneate or truncate at base, not auriculate, coarsely dentate; upper leaves minutely auriculate, dentate. Racemes ebracteate, with a terminal cluster of sterile flowers, not secund; fruiting pedicels divaricate-ascending, straight, 2–5 mm. Flowers: sepals forming subcampanulate calyx, pale green to purplish, densely pubescent, ovate, 4–6 mm, not keeled; petals light purple, with white margins, 6–9 mm; blade crisped, 2–3 x 1–1.5 mm; claw 5–6 mm, wider than blade; filaments in 3 pairs of unequal length; adaxial pair exserted, united to near apex, 5–6 mm; abaxial pair united to a little beyond middle, 4–5 mm; lateral pair 3–4 mm; anthers of adaxial stamens sterile, 0.3–0.5 mm; anthers of abaxial and adaxial stamens fertile, 1.5–1.8 mm. Fruits 4–8.5 cm x 2–2.5 mm, divaricate-ascending to suberect, straight, flattened; valves hispid-hirsute, with a prominent midvein; gynophore 0.1–0.3 mm; replum straight; style 0.4–1 mm; stigma slightly 2-lobed; ovules and seeds 34–66 per fruit. Seeds ovate to suborbicular, 1.6–2 x 1.2–1.8 mm; wing continuous, 0.2–0.35 mm wide. 2n = 28.
Habitat: talus or rocky outcrops (Franciscan formation, largely on chert) and sparsely vegetated openings in grassland or chaparral.
Elevation: 600–1200 m.
Distribution: United States (California/Contra Costa Co., Mt. Diablo).