Draba maguirei subsp. stonei

Perennials with branched caudices forming loose, spreading mats to 20 dm in diam.; caudex branches terminating in leaf rosettes that produce either leafy, sterile, short shoots or scapose flowering stems in later growing seasons. Rosette leaves appressed to ground surface or slightly recurved, oblanceolate, 0.5–1.2 cm × 1.5–3 mm; margins with stalked, mostly 2- and 3-rayed trichomes to 0.7 mm long; leaf surfaces (especially abaxial) with scattered trichomes. Sterile short shoots unbranched, to 2 cm long, leafy, with sparse, mostly 2- and 3-rayed trichomes to 0.7 mm long; short shoot leaves alternate and recurved proximally, tufted and ascending distally, narrower and more pubescent than rosette leaves. Flowering/fruiting stems unbranched, scapose, 0.4–1.3 dm, sparsely hirsute proximally with simple and/or 2- and 3-rayed, short-stalked trichomes to 0.7 mm long. Racemes 5–19-flowered, ebracteate, elongating in fruit; rachises straight to slightly flexuous, glabrous. Fruiting pedicels divaricate-ascending to ascending, gently upcurved or straight, the lowermost 5–12(20) mm long, glabrous. Flowers: sepals elliptic, 3–4 × 1.2–2 mm, glabrous or with rare, mostly simple trichomes; petals yellow, oblanceolate, often shallowly bilobed at apices, 5–7 × 1.2–2 mm; anthers broadly sagittate, 0.5–0.9 × 0.4–0.5 mm when shedding pollen. Fruits ± flattened parallel to the septum, not twisted, ovate to lanceolate, bilaterally symmetric to slightly falcate, styles 0.5–1.4 mm, mature ovaries 3–7.5 × 2–3.3 mm; valves with scattered, simple trichomes to 0.3 mm long (occasionally glabrous); ovules 4–10 per ovary. Seeds ovoid to oblong, 1.6–2 × 1.3–1.6 mm. Chromosome number 2n = 16.

Similar to subsp. maguirei but differing in: (1) rosette leaves with trichomes common on margins and surfaces (vs. usually sparse on margins and absent on surfaces); (2) leaf trichomes mostly 2- to 3-rayed (vs. many 4-rayed); (3) fruits and proximal portion of flowering stems usually sparsely pubescent (vs. mostly glabrous); (4) chromosome number of 2n = 16 (vs. 32); and 5) occurrence in low- to mid-montane habitats <2450 m elevation (vs. high-montane to subalpine habitats >2450 m).

-Mike Windham