12. Caulanthus inflatus S. Watson, Proc. Amer. Acad. Arts 17: 364. 1882; Streptanthus inflatus (S. Watson) Jepson, Fl. Francisc. 257. 1891. TYPE: United States, California, Mojave Desert near railroad, 1880, J. G. Lemmon 15 (lectotype designated by Payson (1923), GH!).

Herbs, annual, glabrous or sparsely pilose basally with simple trichomes, glaucous. Stems 1.5–9.7 dm, erect, simple or branched above, glabrous or sparsely pilose, hollow, strongly inflated and to 4 cm in diam. at the middle. Basal leaves rosulate; petiole 0.5–5 cm; blade obovate to oblanceolate, 1–13 x 0.5–6 cm, glabrous or sparsely pilose, margin entire or dentate-sinuate; uppermost cauline leaves sessile, ovate to lanceolate, 1–20 x 0.5–7 cm, base amplexicaul, margin entire. Racemes without a terminal cluster of sterile flowers, ebracteate, densely flowered, elongated in fruit; fruiting pedicels ascending to divaricate, 3–12 mm, sparsely to densely pilose, or glabrous. Sepals dark purple at least apically, whitish basally, narrowly ovate to lanceolate or oblong-lanceolate, 5.5–14 ´ 2–3 mm, erect, unequal and the adaxial sepal slightly smaller or narrower, keeled; petals purple, 9–14 mm; blade 3–4 x 1.5–2 mm, crisped; claw oblanceolate to oblong, 6–10 x 1.5–3 mm; filaments in 3 unequal pairs, median pairs connate, adaxial pair 7–10 mm, abaxial pair 4–8 mm, lateral pair 3–5 mm; anthers narrowly oblong, 2–4 mm, equal; ovules 58–82 per ovary. Fruits 3.5–12.7 cm ´ 2–3 mm, erect to ascending, terete; valves with a prominent midvein; style obsolete or rarely to 0.4 mm; stigma strongly 2-lobed, lobes opposite valves. Seeds 1.5–3 x 0.7–1.7 mm; cotyledons entire.

Flowering: Feb–Jun.

Habitat: desert plains, dry hillsides.

Elevation: 200–1400 m.

Distribution: United States (C and S California).