21. Streptanthus howellii S. Watson. Proc. Amer. Acad. Arts 20: 353. 1885; Cartiera howellii (S. Watson) Greene, Leafl. Bot. Observ. Crit. 1: 226. 1906. TYPE: United States, Oregon, Curry Co., Coast Mts., 12 June 1884, Thomas J. Howell 39 (holotype, GH!).
Herbs, perennial, glabrous, glaucous; caudex simple or branched. Stems 3–8 dm, simple or rarely branched above. Basal leaves not rosulate, petiolate, rather fleshy, soon withering; middle cauline petiolate, broadly spatulate-obovate to suborbicular, 1.5–10 x 0.5–4.5 cm, entire to repand or obtusely dentate; upper leaves narrowly oblong-oblanceolate to linear, cuneate to attenuate at base, not auriculate, entire. Racemes ebracteate, without a terminal cluster of sterile flowers, lax; fruiting pedicels divaricate to ascending, straight, 0.7–1.7 cm. Flowers: sepals forming subcampanulate calyx, purplish, oblong, 5–8 mm, not keeled; petals maroon to purple, 8–12 mm; blade 3–5 x 0.5–1 mm, not crisped; claw 5–7 mm, wider than blade; filaments in 3 pairs of unequal length, free; adaxial pair 6–7 mm; abaxial pair 5–6 mm; lateral pair 4–5 mm; anthers of all stamens fertile, 3–3.5 mm. Fruits 5.5–12 cm x 2.5–3.2(–3.5) mm, divaricate-ascending, straight to slightly curved inwards, not torulose; valves glabrous, with a distinct midvein; gynophore 0.5–5 mm; replum straight; style 0.3–3 mm; stigma subentire; ovules and seeds 24–44 per fruit. Seeds broadly oblong to suborbicular, 3–4 x 2–3 mm; wing continuous, 0.5–1.1 mm wide. 2n = 28.
Habitat: dry serpentine slopes and ridges in open conifer-hardwood forests.
Elevation: 600–800 m.
Distribution: United States (N California/Del Norte and Siskiyou counties, S Oregon/Curry and Josephine counties).