Pachylophus macroglottis Rydberg, Bull. Torrey Bot. Club 30: 259. 1903; Oenothera cespitosa var. macroglottis (Rydberg) Cronquist; P. hirsutus Rydberg

Herbs acaulescent or short-caulescent, hirsute and glan­dular puberulent, or glabrous. Stems (if present), usually unbranched, rarely with 1–several short laterals, 4–8 cm. Leaves (6.8–)9.5–23(–32) × (1.3–)2.4–4.5(–6.5) cm; petiole (3–)4–11(–14) cm; blade oblanceolate to spatulate, margins often undulate, usually regularly to irreg­ularly dentate, rarely coarsely and irregularly pinnately lobed. Flowers: floral tube (45–)75–110(–153) mm; sepals (22–)30–45(–50) mm; petals fading pink to pale rose, (21–)35–43(–50) mm; filaments (16–)19–28(–35) mm, anthers (10–)12–17 mm; style 85–180 mm. Capsules somewhat curved, lanceoloid-cylindrical to cylindrical, symmetrical throughout, sometimes slightly flattened on one side at base, (17–)25–45(–56) × 5–8 mm, valve margins with conspicuous, nearly smooth to irregular undulate ridge; pedicel 2–7 mm. Seeds narrowly obovoid, 2.5–3 × 1–1.4 mm, embryo 1/2 of seed volume, surface minutely papillose to reticulate; seed collar forming narrow slit above raphe with a slightly sunken membrane, margin entire or obscurely sinuate distally. 2n = 14, 28.

Flowering May–Jul(–Sep). Open, igneous rocky slopes, talus, roadcuts, open or shaded and sandy or gravelly sites along streams, rarely on shale, in upper pinyon-juniper woodlands, Gambel oak scrub, ponderosa pine forests, ponderosa pine-Douglas fir forests, spruce-fir-lodgepole pine forests; 2000–3100 m; Colo., N.Mex., Utah, Wyo.