Amer. J. Bot. 4: 266. 1917.
Perennials; caudex branched (branches loose or compact, sometimes terminating in sterile rosettes); scapose. Stems unbranched, (0.15–)0.3–0.8(–1.1) dm, usually densely pubescent throughout, trichomes stalked, 2–5-rayed, 0.1–0.4 mm, with subsessile, smaller, 4–8-rayed ones, rarely proximally with some simple trichomes. Basal leaves rosulate; subsessile; petiole margin not ciliate; blade oblanceolate to obovate or linear-oblanceolate, (0.2–)0.3–0.9(–1.5) cm × 1–2.5(–4) mm, margins entire, (not ciliate), surfaces canescent with short-stalked, 8–15-rayed, stellate trichomes, 0.1–0.25 mm. Cauline leaves 0. Racemes (4–)6–18(–23)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. Fruiting pedicels divaricate-ascending to ascending, straight, 4–9(–13) mm, pubescent as stem. Flowers: sepals oblong, 2–3.5 mm, pubescent, (trichomes 4–6-rayed); petals yellow or lemon, oblanceolate to spatulate, 4–6 × 1.5–3 mm; anthers ovate, 0.4–0.6 mm. Fruits ellipsoid to ovoid, plane, inflated at least basally, 2–5(–6) × 1.5–2.5(–3.5) mm; valves pubescent, trichomes 2–4-rayed, 0.03–0.2 mm (some or all rays spurred); ovules 4–10(–12) per ovary; style 0.2–0.9(–1.2) mm. Seeds ovoid, 1–1.6 × 0.7–1.2 mm. 2n = 20.
Phenology: Flowering May–Jul.
Habitat: Granite outcrops and rocky slopes in open pine forests
Elevation: 2100-2800 m
Draba sphaerocarpa is a distinctive species known only from Boise, Custer, Idaho, and Valley counties in central Idaho.