Steyermark’s milkwort

Flowers (2.4–)3–5.1(–5.4) mm; sepals eciliate or infrequently with a few proximal cilia; keel beak deltate or rounded, often obscure, (0–)0.1–0.3(–0.5) mm, base width equal to or greater than length; staminal column glabrous adaxially, except marginally. Seeds (1.7–)1.9–2.7 mm, body (excluding aril and pubescence) (1–)1.1–1.5(–1.7) mm. 2n = 18.

Flowering summer. Crevices of limestone boulders and cliffs in mesic oak-maple canyons, chaparral, open coniferous forests; 1500–2400 m; N.Mex., Tex.

Variety rimulicola occurs in the Guadalupe Mountains in New Mexico (Eddy County) and Texas (Culberson County). It is also known from the Sierra Diablo Mountains of Texas (Culberson and Hudspeth counties).