Hymenolobus pubens A. Gray, Smithsonian Contr. Knowl. 3(5): 9. 1852; Capsella pubens (A. Gray) S. Watson; Mancoa pubens (A. Gray) Rollins; Poliophyton pubens (A. Gray) O. E. Schulz

Annuals or biennials; (base not woody). Stems erect, unbranched or branched distally, (2-)3-7.5(-11.5) dm, trichomes sessile. Basal leaves: petiole 0.4-2 cm; blade oblanceolate to oblong, 2-8 (-11) cm × 05-20(-30) mm, margins coarsely dentate or somewhat pinnatifid, surfaces with sessile trichomes. Cauline leaves sessile; blade oblong to oblanceolate, 1.5-5(-6) cm × 3-12(-15) mm (smaller distally), base truncate or broadly cuneate, margins coarsely dentate, pubescent as basal. Racemes considerably elongated in fruit. Fruiting pedicels divaricate, (slightly curved upward or straight), (6-)8-15(-18) mm, (trichomes appressed). Flowers: sepals widely spreading, 1.5-2.5 × 1-1.5 mm; petals spatulate, 1.5-2.5 × 0.7-1.2 mm, claw obscurely differentiated from blade, to 1 mm; filaments spreading, 1.5-2.5 mm, equal to petals; anthers 0.7-1 mm. Fruits ascending, straight, not torulose, oblong to ovoid, slightly angustiseptate to subterete, 0.5-0.8(-0.9) cm × 3-4(-5) mm; ovules (60-)70-110 per ovary; style 0.3-0.8(-1) mm. Seeds biseriate, 0.6-0.8 × 0.4-0.5 mm.

Flowering late Apr-early Aug. Spring-fed areas, canyons, draws, streamsides, shaded moist grounds, grassy plains, creek beds, tobosa flats; 1200-1500 m; Ariz., Tex.; Mexico (Coahuila, Sonora).

Halimolobos pubens appears to be restricted in Texas to Brewster, Jeff Davis, Presidio, and Reeves counties. It has recently been reported from Cochise County, Arizona. For a detailed discussion of its generic disposition, see C. D. Bailey et al. (2007).