8. Physaria arizonica (S. Watson) O’Kane & Al-Shehbaz, Novon. 12: 321. 2002.
Lesquerella arizonica S. Watson, Proc. Amer. Acad. Arts 23: 254. 1888; L. arizonica var. nudicaulis Payson; Physaria arizonica var. andrusensis N. D. Atwood, S. L. Welsh & L.C. Higgins
Perennials; caudex branched, (cespitose); densely (silvery gray) pubescent, trichomes (sessile or subsessile), (4-), 6-, or 8-rayed, rays fused at base, furcate or bifurcate, (slightly umbonate, tuberculate throughout). Stems simple or few to several from base, erect, (unbranched, slender), 0.2-1(-1.5) dm. Basal leaves (densely tufted, not rosulate, reflexed in age); blade obovate to oblanceolate, 0.7-2(-3) cm, margins usually entire, sometimes repand or shallowly dentate, (apex acute). Cauline leaves similar to basal, becoming narrower distally, somewhat reflexed, (distal) blade linear or narrowly oblanceolate, 0.5-2.5(-5.5) cm. Racemes dense, often subcorymbiform. Fruiting pedicels (erect or divaricate-spreading, straight or slightly curved), (3-)5-10(-15) mm. Flowers: sepals (green or greenish yellow), ovate or broadly ovate, 3.5-6.5 mm, (lateral pair subsaccate, cucullate, median pair thickened, slightly cucullate apically); petals (spreading), oblanceolate to obovate, 5.5-8(-10) mm, (claw erect). Fruits (sessile or substipitate), suborbicular to ovoid or ellipsoid, slightly inflated, 4-7 mm; valves pubescent outside, trichomes substipitate, spreading, sometimes sparsely pubescent inside, trichomes sessile, smooth; ovules 4-10(-16) per ovary; style (0.5-)1-2(-4) mm (shorter than fruit). Seeds flattened. 2n = 10.
Flowering Apr-Jun. Sandy and gravelly soils, limey knolls or limestone chip, often in open stands of sagebrush-pinyon, pinyon-juniper, Gambel oak and sometimes ponderosa pine; 1000-2200 m; Ariz., Utah.
The circumscription of Physaria arizonica here is quite broad and includes plants that have densely tufted basal leaves and relatively few or no cauline leaves; plants that are loosely tufted and have several cauline leaves; and plants that have a strongly branched caudex, leafy stems, and sterile shoots (var. andrusensis). Additional study is needed to understand the pattern of variation in this complex species; all of the characters given above vary considerably.