Erythranthe nasuta

Annuals, fibrous-rooted or slender-taprooted. Stems erect to ascending-erect or decumbent, simple or branched from proximal nodes, 4-angled, sometimes shallowly 4-winged, thin-wiry, or fistulose, 2–35(–100) cm, glabrous except for a consistently small, villous-glandular area just above nodes, sometimes hirtellous distally. Leaves basal and cauline or basal not persistent; petiole: proximals to medials 3–35 mm, base narrowly flanged, distals 0 mm; blade ± red tinged abaxially or purple-spotted, palmately 3–5-veined, elliptic-ovate to broadly ovate, suborbicular, or depressed-ovate, (5–)10–49(–80) × (3–)10–25(–60) mm, as long as wide or wider than long, proximals largest and persistent, base cuneate to truncate or subcordate, margins irregularly dentate to dentate-serrate or nearly lacerate-dentate, commonly doubly toothed, main teeth 4–9 per side, sometimes sublacerate to sublyrate basally, apex acute to obtuse, surfaces glabrous, sometimes hirtellous, hairs dull, terete, sharp-pointed, eglandular. Flowers plesiogamous, (1 or)2–12(–20), from distal nodes, sometimes from medial to distal, chasmogamous or cleistogamous. Fruiting pedicels (3–)7–20(–40) mm, longer than subtending leaves, glabrate, sometimes glandular-villous adaxially at axils. Fruiting calyces nodding 30–180º, usually purple-tinged or -spotted, ovoid-campanulate, inflated, sagittally compressed, (5–)10–15(–19) mm, glabrous or minutely hirtellous to appressed-hirtellous, minutely short-ciliate at sinuses, throat closing, adaxial lobe usually longer than abaxial, slightlty falcate. Corollas yellow, throat usually red-spotted, abaxial limb base usually with a red splotch, bilaterally symmetric, weakly bilabiate; tube-throat broadly cylindric, (5–)8–12 mm, exserted (0–)1–2 mm beyond calyx margin; limb expanded 6–12 mm. Styles minutely scabrous or glabrous. Anthers included, glabrous. Capsules included, (4–)5–9(–10) mm. 2n = 26, 28, 56.

Phenology: Flowering (Mar–)Apr–Jun(–Jul).
Habitat: Cliff faces, ledges, crevices, and bases, wet rocks in rivers, streamsides, sand bars, mossy seeps, wet clay banks, moist fields, sandy soils, depressions over granite, roadsides.
Elevation: (0–)600–2300(–3200) m.

B.C., Ariz., Calif., Idaho, Nev., N.Mex., Oreg., Utah, Wash., Mexico (Baja California, Sonora).

Discussion

Erythranthe nasuta is characterized by its annual duration (fibrous-rooted), four-angled stems, broadly ovate leaves commonly with irregularly toothed margins, calyces with longish, protruding adaxial lobes, and short corollas (all autogamous, chasmogamous or cleistogamous). Flowers may vary significantly in size, even on a single plant. Plants commonly produce tiny cleistogamous flowers on branches (usually at the base of the plant) separate from those with larger flowers. At least the distal and bracteal leaves consistently have hirtellous to hirsutulous adaxial surfaces, even in the smallest of plants. Glandular vestiture is produced only in the axils. Some plants, apparently at the upper limits of populational variability, produce thick-fistulose stems to 100 cm, large leaves (to 80 × 60 mm), and large fruiting calyces (16–19 mm).

Plants described as Mimulus sookensis (B. G. Benedict 1993; Benedict et al. 2012) are tetraploid and have been hypothesized to have arisen as alloploids between Erythranthe nasuta and E. microphylla in two or more independent events. In morphology, however, they are indistinguishable from E. nasuta and are treated here within it. In contrast, experimental hybrids and naturally occurring nasuta-microphylla hybrids apparently of contemporary origin are intermediate in morphology (see review by G. L. Nesom 2013e). The tetraploid occurs from northern California to southwestern British Columbia (A. L. Sweigart et al. 2008; Benedict et al. 2012).

Selected References

None.

Lower Taxa