Watson’s milkwort

Subshrubs, multi-stemmed, 0.5–5 dm, branched throughout; from thickened caudex. Stems erect, sometimes laxly so, puberulent or subglabrous, hairs incurved. Leaves alternate; sessile or subsessile; blade usually linear-lanceolate to linear, sometimes falcate-linear with reflexed tip, 4–15 × 0.3–1 mm, base obtuse or acute, apex acute to acuminate, surfaces usually puberulent, rarely subglabrous, hairs incurved. Racemes subcapitate, 0.5–1.4(–2.5) × 1 cm; peduncle 0–0.5 cm; bracts deciduous, ovate to lanceolate-ovate. Pedicels 0.5 mm, glabrous. Flowers white, greenish or purplish veined, keel pink to purplish brown, often yellow-green distally, (3.7–)4–6 mm; sepals oblong-ovate, 1.3 mm; wings spatulate-obovate, (3.5–)4–6 × 1.3–1.6 mm, apex obtuse or acute, sometimes minutely apiculate; keel 2.8 mm, crest 2-parted, with 3 divided lobes on each side. Capsules oblong-ellipsoid to oblong, 2.3–3.5 × 1.6 mm, abaxial locule not winged, adaxial locule slightly longer, not or obscurely winged. Seeds 2.5–3 mm, puberulent, coat with rows of pits 0.05 mm wide; aril 1–1.9 mm, lobes 1/2 to subequal to length of seed. 2n = 16.

Flowering early spring. Stony limestone slopes; 1800–1900 m; Tex.; Mexico (Chihuahua, Coahuila, Nuevo León).

Polygala watsonii is known in the flora area from a single collection from the Glass Mountains in Brewster County (T. L. Wendt 1979).