New Mexico milkwort

Polygala rectipilis S. F. Blake, Contr. Gray Herb. 47: 27, plate 1, fig. 14. 1916

Herbs, 1.5–3.5 dm. Stems erect, sometimes laxly so, hairs spreading. Leaves: blade ovate, elliptic, spatulate, or linear proximally, to elliptic, lanceolate, or linear distally, often longer than proximal ones, 4–45(–65) × 1.5–4 mm, base often acute, sometimes cuneate or obtuse, apex acute to acuminate or obtuse, surfaces not translucent-punctate, hairs spreading. Inflorescences terminal or leaf-opposed, racemes, loose, 2–12 ×0.9–1.4 cm; peduncle 0.5–1.5 cm; bracts linear to narrowly ovate. Pedicels 1–5 mm, pubescent. Flowers purplish, wings usually cream or yellow, keel distally yellow or yellowish green, 3.5–6 mm; sepals lanceolate, 2.2–3.5 mm; wings ovate to suborbiculate, 3.5–5.5 × 2.4–4 mm, sparsely pubescent; keel 4–5.7 mm, pubes­cent. Capsules oblong or oblong-ovoid to broadly ellipsoid or subglobose, 6–8 × 4.5–7 mm, not translucent-punctate, glabrous and ciliolate. Seeds 4–4.5 mm; aril 0.6–1 mm, lobes vestigial to 1/4 length of seed.

Flowering (spring–)late summer. Rocky or gravelly soils in desert scrub; 1200–2000 m; N.Mex.; Mexico (Chihuahua, Coahuila, Durango, Zacatecas).

In the flora area, Hebecarpa rectipilis is known only from the type collection in Sierra County.

Hebecarpa rectipilis is very similar to, and may be conspecific with, H. barbeyana; it differs in the spreading hairs (versus incurved), wing sepals usually cream to yellow (versus usually purplish, rarely yellow), and fruits without the small and large size extremes (6–8 versus 5–10 mm). However, given the overlap in wing sepal color and fruit size, these taxa could represent phenotypic (and genotypic?) forms of a single polymorphic entity.