12. Streptanthus cutleri Cory, Rhodora 45: 259. 1943. TYPE: United States, Texas, Brewster Co., ca. 50 mi S of Marathon, 4 mi NE of Black Gap, 2500 ft., 28 Feb 1937, Hugh Cutler 677 (holotype, GH!; isotype, CAS!).
Herbs, annual, glabrous throughout. Stems 2–7 dm, single, usually branched above. Basal leaves subrosulate, petiolate, oblanceolate, 2.5–20 cm, runcinate-pinnatifid; middle cauline leaves petiolate, not auriculate at base, oblanceolate, 4–20 x 1–7 cm, runcinate-pinnatifid; upper leaves undivided, usually entire, reduced. Racemes ebracteate, lax, without a terminal cluster of sterile flowers; fruiting pedicels divaricate-ascending, (0.5–)1–2.7 cm. Flowers strongly zygomorphic; sepals forming campanulate calyx, ascending, dark purple, 8–12 mm, not keeled; petals lavender to purple-lavender, in 2 strikingly unequal pairs; adaxial pair 15–26 mm, blade 8–15 mm, not crisped, claw 7–11 mm, crisped, narrower than blade; abaxial pair undifferentiated into blade and claw, 5–6 mm, crisped; filaments in 3 pairs of unequal length; adaxial pair 8–12 mm; abaxial pair 6–7 mm; lateral pair 3–5 mm; anthers of adaxial stamens fertile, 3–3.5 mm; anthers of abaxial and lateral stamens 4–5 mm. Fruits 3.2–7.5 cm x 4–5 mm, ascending, strongly flattened, straight, not torulose; valves glabrous, with a distinct midvein; gynophore 0.2–0.5 mm; replum straight; style 0.2–0.5 mm; stigma 2-lobed; ovules and seeds 30–46 per fruit. Seeds orbicular, 3–4 mm diam.; wing continuous, 0.5–1 mm wide.
Habitat: talus slopes, rocky hillsides, gravelly and dry stream beds, sand flats, limestone slopes, open scrub or woodland.
Elevation: 450–650 m.
Distribution: Mexico (Coahuila), United States (Texas/Brewster Co.).