Erythranthe percaulis
Phytoneuron 2013-70: 1, figs. 1–5. 2013.
Annuals, fibrous-rooted. Stems erect or slightly ascending from base, often purplish, simple or few-branched from basal nodes, 7–28 cm, glabrous. Leaves basal and cauline; petiole: basal and proximalmost cauline 5–10 mm or cauline 0 mm; blade often spreading at right angles to stem, purple, palmately 3–5-veined, narrowly ovate, rhombic-elliptic, ovate to lanceolate, or elliptic-lanceolate to ovate or oblong-ovate, 7–10 mm, cauline even-sized or slightly smaller distally, 4–10 mm, base truncate to attenuate, margins entire or proximals shallowly sinuate, serrations 2–4, shallow, apex rounded, surfaces glabrous. Flowers herkogamous, 8–12, usually on distal 2/3 of stem, not clustered, chasmogamous. Fruiting pedicels 15–35 mm, glabrous. Fruiting calyces sharply wing-angled, urceolate to urceolate-campanulate, inflated, sagittally compressed, (4–)5–6 mm, glabrous, throat closing. Corollas yellow, throat floor with a few red dots, proximal middle lip base with a larger red splotch, bilaterally symmetric, bilabiate; tube-throat cylindric-funnelform, 4–6 mm, exserted 2–3 mm beyond calyx margin; limb expanded 4–5 mm, palate ridges yellow, densely hairy. Styles glabrous. Anthers included, glabrous. Capsules included, 3 mm.
Phenology: Flowering May–Jun.
Habitat: Soil pockets, crevices, and boulders on serpentine cliffs, slopes, and roadcuts.
Elevation: 2800 m.
Discussion
Erythranthe percaulis was described from only the type collection from Serpentine Canyon of the Feather River in Plumas County, but the type locality has recently been relocated and the population determined to comprise many thousands of individuals (S. Schoenig 2016). Plants are characterized by their completely glabrous vestiture, terete and mostly simple stems, small leaves on relatively widely spaced nodes, small calyces, and small, yellow corollas with herkogamous arrangement of stigma and anthers.