Phytoneuron 2012-39: 34. 2012.
Annuals, fibrous-rooted. Stems erect, simple or branched from base, weakly 4-angled, 8–20 cm, glabrous. Leaves basal and cauline; petiole 0 mm; blade palmately 3–5-veined, broadly ovate, 7–18 × 5–12 mm, base rounded, margins denticulate, apex acute, surfaces glabrous, rarely sparsely puberulent. Flowers herkogamous, 2–20, from proximal to distal nodes. Fruiting pedicels 6–7 mm, shorter than subtending leaves, glabrous. Fruiting calyces campanulate, 9–11 × 5–6 mm, margins subtruncate, glabrous, sometimes densely papillate at flowering with tiny, 1-celled, eglandular hairs, these apparently deciduous by fruiting, lobes reduced, subequal. Corollas rose red, throat pink lined with rose red and a yellow patch, abaxial ridges yellow, bilaterally symmetric, weakly bilabiate; tube-throat cylindric-funnelform, 8–11 mm, exserted beyond calyx margin; limb expanded 7–10 mm. Styles glabrous. Anthers included, minutely villous-hirsute. Capsules included, 5–9 mm.
Phenology: Flowering May–Jul(–Oct).
Habitat: Drying pond beds, creek banks, yellow pine, yellow pine-Libocedrus woodlands.
Elevation: 1000–1900 m.
In addition to the features noted in the key and descriptions, the fruiting calyces of Erythranthe grayi are distinctly more inflated than those of E. acutidens and E. inconspicua. G. L. Nesom (2012g) maintained E. grayi as distinct from E. acutidens, relying primarily on fruiting pedicel length (see key above), but the two have nearly identical ranges (Tuolumne County south to Kern County), and study of additional collections suggests that only a single species may be represented.