Beaked spiny polygala, desert or notch-beaked milkwort

Polygala subspinosa S. Watson var. heterorhyncha Barneby, Leafl. W. Bot. 3: 194. 1943; P. heterorhyncha (Barneby) T. Wendt

Subshrubs, multi-stemmed, mat-forming, 1–2.5 dm. Stems pros­trate to laxly erect, often glaucous, glabrous or pubes­cent, hairs spreading. Leaves sessile; blade ovate, elliptic, or obovate, 4–20 × 2–12 mm, base cuneate, rounded, or nearly clasping, apex acute or rounded, surfaces pubescent, hairs spreading. Racemes terminal, to 3.5(–5) × 1.5–3 cm; rachis thorn-tipped; peduncle 0.2–0.3 cm; bracts deciduous, ovate, elliptic, or linear. Pedicels (3–)4–8(–9.5) mm, glabrous or pubescent. Flowers pink, wings usually pink, keel distally yellow, (7.5–)9.5–13.5 mm; sepals deciduous, elliptic to ovate, lower sepals mostly obovate, (2–)2.5–6 mm, pubescent; wings obovate to elliptic-obovate, (6.5–)8–12.5 × (2.5–)3–5.5 mm, glabrous or sparsely pubescent; keel (6–)7.5–11.2 mm, sac glabrous, beak oblong, with 1 or 2 prominent invaginations along abaxial side formed by sinuate excess tissue, (1.4–)2–4 × (0.6–)0.8–1.3 mm, glabrous. Capsules ellipsoid-ovoid to obo­void, 4.2–7.8 × 3.7–7 mm, base cuneate to rounded, margins with very narrow and even wing, pubescent or glabrous. Seeds 3–4.4 mm, most densely pubescent apically, proximal 1/2 sparsely and unevenly pubescent or glabrous; aril 1.3–2.6 mm, lobes 1/4–1/2 length of seed. 2n = 36(or 38).

Flowering spring–early summer. Sandy or gravelly open slopes and flats in desert scrub; 900–1600 m; Calif., Nev.

Rhinotropis heterorhyncha is known from the Funeral Mountains of Inyo County, California, in the Mojave Desert region, and from adjacent areas of southern Nevada.