Castilleja ambigua var. meadii
Phytoneuron 2012-68: 2, figs. 1, 3–7, 9[left]. 2012.
Stems erect, unbranched, sometimes with a few divaricate-ascending branches from proximal 1/2 of stem above base. Leaves linear or linear-lanceolate to lanceolate, 1 mm wide at base, not fleshy, apex acuminate. Bracts proximally pale greenish, distally white on lobe apices, often becoming entirely greenish with age; lobes divaricate-ascending, linear, 8–14 mm, usually arising below mid length. Calyces with all 4 clefts subequal or lateral clefts shallower; lateral clefts 2–3 mm, 25% of calyx length. Corollas 14–21 mm; beak pale, off-white, pale-yellow, green with margins off-white, or yellow, sometimes orange, 1–4 mm; abaxial lip pale-yellow; teeth white to green.
Phenology: Flowering Apr–Jun(–Jul).
Habitat: Seasonally wet meadows with volcanic substrates in oak-pine woodlands or chaparral, shallow vernal pools, ephemeral stream margins.
Elevation: 400–500 m.
Variety meadii is limited to vernally wet habitats, growing over rocks of the Sonoma Volcanic Formation in central Napa County near Atlas Peak. All known populations are under private ownership, and the variety is of conservation concern due to its very limited range. For the present, all populations except one are protected by conservation easements. Variety meadii often grows alongside, but does not hybridize with, Castilleja attenuata and C. densiflora. Ongoing study of annual species of Castilleja suggests this variety is genetically distinctive and may deserve full species status (S. J. Jacobs et al. 2018).