Castilleja flava var. flava
Leaves 0–5-lobed. Bracts distally pale to bright yellow, sometimes to light orange; lobes long. Calyces proximally green, sometimes purple, distally yellow to light orange, 13–28 mm; abaxial clefts 8–16 mm, adaxial 4–8(–15.5) mm, abaxial ca. 60% of calyx length, adaxial 30–50% of calyx length, slightly to much more deeply abaxially in front than adaxially, lateral 1.5–4 mm, 5–15% of calyx length; lobes lanceolate to narrowly triangular. Corollas 13–30 mm; beak 5–12 mm; abaxial lip 1–2 mm.
Phenology: Flowering Jun–Aug(–Sep).
Habitat: Montane to subalpine.
Elevation: 900–3000 m.
Colo., Idaho, Mont., Nev., Utah, Wyo.
Variety flava often differs from var. rustica in the color of the bracts, as well as in the structure of the calyx and corolla. They also have different ranges, with var. rustica replacing var. flava in southwestern Idaho and northeastern Oregon. The latter is found in the northern Great Basin and central Rocky Mountains. Variety flava hybridizes with Castilleja viscidula in Elko County, Nevada. Hybrids between C. angustifolia var. angustifolia and var. flava are known from the western slopes of the Big Horn Mountains, Wyoming. M. Ownbey (1959) reported from the same region a hybrid swarm between var. flava and C. linariifolia.