36. Physaria gordonii (A. Gray) O’Kane & Al-Shehbaz, Novon. 12: 323. 2002.
Vesicaria gordonii A. Gray, Boston J. Nat. Hist. 6: 149. 1850 (as gordoni); Alyssum gordonii (A. Gray) Kuntze; Lesquerella gordonii (A. Gray) S. Watson; L. gordonii var. densifolia Rollins; Physaria gordonii subsp. densifolia (Rollins) O’Kane & Al-Shehbaz; P. gordonii var. densifolia (Rollins) B. L. Turner
Annuals, biennials, or perennials; (short-lived); with a fine taproot; usually densely pubescent, trichomes (sessile or short-stalked), 4-7-rayed, rays distinct and furcate or bifurcate, (nearly smooth to finely tuberculate). Stems several from base, erect to decumbent or prostrate, (unbranched or branched, sometimes densely leaved), 1-3.5(-4.5) dm. Basal leaves: blade obovate to broadly oblong, 1.5-5(-8) cm, margins lyrate-pinnatifid, dentate, or entire. Cauline leaves: (proximal sometimes petiolate, distal sessile); blade linear to oblanceolate, often falcate, 1-4(-7) cm, (proximal with base sometimes cuneate), margins entire, repand, or shallowly dentate. Racemes dense. Fruiting pedicels (divaricate-ascending, sigmoid or, sometimes, nearly straight), 5-15(-25) mm. Flowers: sepals elliptic or oblong, 3-6.5 mm, (lateral pair subsaccate, median pair thickened apically, cucullate); petals (widely spreading at anthesis, yellow to orange, claw sometimes whitish), cuneate, obdeltate, or obovate, (tapering to claw), 5-8(-10) mm, (claw often widened at base). Fruits (shortly stipitate), subglobose, not or slightly compressed, (3-)4-8 mm; valves (not retaining seeds after dehiscence), glabrous throughout; replum as wide as or wider than fruit; ovules (8-) 12-20(-26) per ovary; style (1.5-)2-4(-5) mm. Seeds flattened. 2n = 12, 32.
Flowering Feb-Jul. Sandy or light soils, rocky plains, caprock ledges, gravelly brushland, sandy desert washes, stream bottoms, pastures, roadsides, abandoned fields; 150-1700 m; Ariz., Kans., N.Mex., Okla., Tex., Va.; Mexico (Chihuahua, Sonora).
Physaria gordonii was reported from Virginia in 1987 by Robert Wright from a Hampton Shale roadcut along the Blue Ridge Parkway, where it was probably a short-lived waif.
Subspecies densifolia, of Lincoln County, New Mexico, of which there is now more material than Rollins had available in 1993, appears to represent a suite of environmentally determined, variable, and intergrading characteristics that does not merit taxonomic recognition.