Spiderflower

Cleome multicaulis de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 1: 240. 1824; C. sonorae A. Gray; Peritoma sonorae (A. Gray) Rydberg

Annuals, 20-60 cm. Stems unbranched or sparsely branched; glabrous. Leaves: petiole 0.5-1.5 cm; leaflets 3, blade linear to elliptic, 1-2 × 0.1 cm, margins entire, apex long-acuminate, surfaces glabrous. Racemes 1-3 cm (6-40 cm in fruit); bracts unifoliate, obovate to spatulate, 2-15 mm. Pedicels 7-15 mm. Flowers: sepals persistent, distinct or slightly connate basally, yellow, lanceolate, 1.6-2.6 × 0.8-1.2 mm, margins denticulate, glabrous; petals white, pink, or rose, oblong to ovate, 4-5 × 1-1.3 mm; stamens yellow, 4-5 mm; anthers 1.9-2.6 mm; gynophore 10-20 mm in fruit; ovary 3-6 mm; style 0.5-0.8 mm. Capsules (reflexed) not inflated, 15-25 × 1.5 mm, striate, (glabrous). Seeds 10-20, gray to black, triangular (sharply angled), 6-15 × 2-2.5 mm, (acute at both ends) rugose.

Flowering summer. Dry to moist open ground, often in saline or volcanic soils; of conservation concern; 700-2000(-2300) m; Ariz., Colo., N.Mex., Tex., Wyo.; Mexico (Coahuila, Distrito Federal, Jalisco, México, Sonora).