Mexican clammyweed

Cleome uniglandulosa Cavanilles, Icon. 4: 3, plate 306. 1797; Polanisia dodecandra (Linnaeus) de Candolle subsp. uniglandulosa (Cavanilles) H. H. Iltis

Perennials, 40-80 cm. Stems sparsely or profusely branched; hairs stalked, glandular throughout. Leaves: petiole green to purple, angled, 1.5-4.5(-6) cm, (glandular); leaflet blade broadly elliptic to oblanceolate, 2-4 × 1-2 cm, margins entire, apex obtuse, mucronulate, surfaces sparsely glandular. Racemes 5-20 cm (10-30 cm in fruit); bracts unifoliate, ovate, 8-12 mm. Pedicels 10-25(-40) mm. Flowers: sepals purple, oblong, 3-6 × 1.5-2.5 mm, margins entire, apex acuminate, glandular; petals white, narrowly spatulate, clawed, abaxial pair 10-20 × 2-3(-5) mm, apex emarginate to lacerate, adaxial pair 15-30 × 3-5 mm, apex emarginate; nectary glands bright orange, not conspicuous (in fruit); stamens 20-27, exserted, purple, 20-50 mm; anthers purple, 1-1.3 mm; gynophore 0-2 mm in fruit; ovary 5-10 mm; style deciduous in fruit, 20-40 mm; stigma purple. Capsules (somewhat inflated), 60-100 × 7-10 mm, reticulate, glandular. Seeds 20-65, dark reddish brown, globose to oblong, 1.5-2 mm, smooth. 2n = 20.

Flowering spring-fall. Pinyon, juniper, and oak woodlands, arroyos, riverbeds, roadsides, pastures; 300-800 m; N.Mex., Tex.; Mexico.

Polanisia uniglandulosa is the only perennial species of the genus, notable for its large, showy, white petals and silky-iridescent seed testa.