Plants 7-15(-25) cm; scape glabrous. Caudices not obvious at anthesis; roots reddish, bulblets usually present. Leaves (2.5-)3-8(-10) × 0.5-1.5(-1.8) cm; petiole usually not winged; blade oblanceolate to narrowly spatulate, base usually slightly decurrent onto stem, gradually tapering to petiole, margins entire, sometimes slightly undulate, surfaces glabrous. Inflorescences 1-5(-8)-flowered; bracts linear to narrowly lanceolate, 2-6 mm, glabrous. Pedicels 1-2(-3.5) cm, glabrous. Flowers: calyx green, 3.5-6 mm, glabrous, tube 2-3 mm, lobes 5, 2.5-4.5 mm; corolla tube usually yellow, sometimes white with dark maroon, thick, wavy ring, lobes 5, usually magenta, sometimes white, 5-9(-12) mm; filaments connate, tube dark maroon, 2-3.5 × 1-1.5 mm; anthers 3-4 mm; pollen sacs yellow, streaked with purple, connective dark maroon, transversely rugose, (infrequently seemingly longitudinally wrinkled); stigma not enlarged compared to style. Capsules tan, valvate, cylindric-ovoid, 6-10(-13) × 3-4.5 mm, glabrous; walls thin, pliable. Seeds without membrane along edges. 2n = 66.

Flowering summer. Moist slopes, mainly shady places in conifer woodlands or in meadows and along stream banks; 2100-4000 m; Calif.

Dodecatheon subalpinum is known from the high western slopes of the central and southern Sierra Nevada from Tuolumne County to Tulare County. This high-elevation ecotype might be considered a variety of D. hendersonii, for which the epithet yosemitanum H. Mason is available.