31. Streptanthus polygaloides A. Gray, Proc. Amer. Acad. Arts 1: 519. 1865; Microsemia polygaloides (A. Gray) Greene, Leafl. Bot. Observ. Crit. 1: 89. 1904. TYPE: United States, California, on the Tuolumne River, 11 Jun 1863, W. H. Brewer 1615 (holotype, GH!).
Herbs, annual, glabrous throughout, sometimes glaucous. Stems (0.8–)2–8(–10) dm, simple or branched above. Basal leaves rosulate, petiolate, soon withered, 2–20 cm, sinuate-dentate or 1- or 2-pinnatifid with broadly linear to filiform lobes; middle cauline leaves linear, 1–10 cm x 1–3 mm, sessile, auriculate, entire; upper leaves similar, reduced. Racemes ebracteate, lax, without a terminal cluster of sterile flowers; fruiting pedicels strongly recurved, 2–5 mm. Flowers markedly zygomorphic; sepals forming urceolate calyx, greenish yellow or purplish, 4–6 mm, not keeled; adaxial pair suborbicular to broadly ovate-cordate, 6–8 mm wide, forming a banner-like hood; abaxial sepal broadly ovate, keeled, 3–4 mm wide; lateral sepals ovate-lanceolate, 1.5–2 mm wide; petals white with brownish veins, 5–8 mm; blade crisped, channeled, 1–3 x 0.7–1.2 mm; claw 4–5 mm, wider than blade; stamens in 3 pairs of unequal length; adaxial pair united, 5–6 mm; abaxial pair free, 4–5 mm; lateral pair 3–4 mm; anthers of adaxial stamens sterile, 0.3–0.7 mm; anthers of abaxial and lateral stamens fertile, 1.5–2 mm. Fruits 2.4–5.6 cm x 1.2–1.7 mm, pendent, straight, flattened, not torulose; valves glabrous, with obscure or somewhat distinct midvein; gynophore 0.1–0.4 mm; replum straight; style 0.8–2 mm; stigma entire; ovules and seeds (10–)18–50 per fruit. Seeds oblong, 1.7–2 x 0.9–1.1 mm; wing distal, 0.2–0.3 mm wide. 2n = 28.
Habitat: serpentine substrates in grasslands, openings chaparral, oak and pine woodlands.
Elevation: 200–1900 m.
Distibution: United States (California).