Subshrubs or herbs, annual (fibrous-rooted or taprooted) or perennial (rhizomatous), terrestrial or semi-aquatic. Stems prostrate to decumbent or erect, terete or 4-angled, glabrous or hairy to glandular-hairy. Leaves basal and cauline, basal, cauline, or basal not persistent, rarely subrosulate (E. linearifolia) or rosulate (E. primuloides); petiole present or absent; blade sometimes thickened or semi-fleshy, not leathery, margins toothed, subentire, or entire, venation acrodromous (veins basal only, sometimes basal and suprabasal). Inflorescences of axillary flowers at medial to distal nodes or at all nodes or rarely solitary; bracts absent or present when distal leaves much reduced. Pedicels present, usually distinctly longer in fruit than calyces; bracteoles absent. Flowers erect, spreading, or nodding; sepals 5 or 3 (in reduced forms), calyx bilaterally or radially symmetric, tubular, sometimes inflated and sagittally compressed with abaxial lobes characteristically upcurving and closing throat or not, lobes 5, rarely 3, all usually ca. equal size or adaxial slightly longer, mostly triangular to deltate, rarely reduced and barely evident; petals 5, corolla deciduous, rarely marcescent, pink, red, crimson, magenta, lavender, purple, or yellow, rarely white, bilaterally symmetric, sometimes ± radially symmetric, ± bilabiate, sometimes regular, sometimes sagittally compressed, abaxial lobes 3, adaxial 2; stamens 4, adnate proximal to middle of corolla, didynamous, filaments glabrous or hairy, staminode 0; ovary 2-locular, placentation axile; stigma bilamellate. Fruits capsules, apex rounded to truncate, dehiscence loculicidal partly to base along both sutures. Seeds 100–2000, brown, narrowly ellipsoid, flattened bilaterally, not winged. x = 7, 8, 9.

Distribution

North America, Mexico, Central America, South America, e, se Asia, introduced in Europe, e Asia (Japan), s Africa, Pacific Islands (New Zealand).

Discussion

Species 114 (86 in the flora).

Erythranthe includes the mostly western American and Asian species with axile placentation and pedicels distinctly longer than the calyces; these were formerly treated within Mimulus in the broad sense. The species of Erythranthe have been divided into 12 sections (W. R. Barker et al. 2012), closely corresponding to the cladistic patterns in the molecular-based phylogenetic analysis by P. M. Beardsley et al. (2004): sect. Achlyopitheca G. L. Nesom & N. S. Fraga (species 1–3), sect. Paradantha (A. L. Grant) G. L. Nesom & N. S. Fraga (species 4–19), sect. Monantha G. L. Nesom & N. S. Fraga (species 20, 21), sect. Monimanthe (Pennell) G. L. Nesom & N. S. Fraga (species 22–24), sect. Erythranthe (species 25–31), sect. Alsinimimulus G. L. Nesom & N. S. Fraga (species 32), sect. Simigemma G. L. Nesom & N. S. Fraga (species 33), sect. Mimulosma G. L. Nesom & N. S. Fraga (species 34–51), sect. Mimulasia G. L. Nesom & N. S. Fraga (species 52), sect. Exigua G. L. Nesom & N. S. Fraga (species 53), and sect. Simiolus (Greene) G. L. Nesom & N. S. Fraga (species 54–86).

Recent taxonomic studies have clarified species definitions, and to some extent relationships, in sect. Achlyopitheca (G. L. Nesom 2012g), sect. Erythranthe (P. M. Beardsley et al. 2003), sect. Mimulosma (M. L. Carlson 2002; J. B. Whittall et al. 2006; Nesom 2012h), sect. Simiolus (G. R. Campbell 1950; Nesom 2012i), and sect. Paradantha (N. S. Fraga 2012). A secondary radiation of species has occurred in Andean South America; C. von Bohlen (1995) studied the Chilean species. A taxonomic summary of the primarily Central American genera Hemichaena Bentham and Leucocarpus D. Don, which are closely related to Diplacus and Erythranthe, respectively, was provided by Nesom (2011d).

A revision of Mimulus in the broad sense was provided by A. L. Grant (1924), followed by a major update and overview by F. W. Pennell (1951) that covered the majority of the western North American species of Erythranthe. A floristic treatment of Mimulus in the broad sense for California by D. M. Thompson (1993) recognized fewer species of Erythranthe than did Pennell, especially in sects. Achlyopitheca, Mimulosma, and Simiolus. The present treatment is more similar to that by Pennell.

A number of the species of Erythranthe currently serve as experimental organisms for various laboratories studying the genetic and genomic basis of adaptation and speciation (M. R. Dudash et al. 2005; C. A. Wu et al. 2008), and sect. Simiolus was the object of intensive investigation from about 1950 until the 1990s by R. K. Vickery and his students, who made hundreds of chromosome counts and interspecific and infraspecific crosses and from those data drew corresponding inferences about isolating mechanisms. Most studies have centered on E. guttata and close relatives (sect. Simiolus), and E. cardinalis and close relatives (sect. Erythranthe), focusing on mating system evolution, reproductive isolation, hybridization and hybrid incompatibility, genetic architecture of floral traits, corolla morphology and pollination, inbreeding phenomena, and epistasis.

The relative position of stigma and anthers is indicated in the descriptions by the terms herkogamous (stigma distinctly above the level of the anthers) and plesiogamous (stigma and anthers in essentially the same level). Herkogamous corollas are generally assumed to be outcrossing except in the relatively smaller corollas where, even if herkogamous, crowding of the stigma and anthers may facilitate occasional autogamy.

Selected References

Argue, C. L. 1986. Some taxonomic implications of pollen and seed morphology in Mimulus hymenophyllus and M. jungermannioides and comparisons with other putative members of the M. moschatus alliance (Scrophulariaceae). Canad. J. Bot. 64: 1331–1337.

Beardsley, P. M., A. Yen, and R. G. Olmstead. 2003. AFLP phylogeny of Mimulus section Erythranthe and the evolution of hummingbird pollination. Evolution 57: 1397–1410.

Campbell, G. R. 1950. Mimulus guttatus and related species. Aliso 2: 319–335.

Carlson, M. L. 2002. Evolution of Mating System and Inbreeding Depression in the Mimulus moschatus (Scrophulariaceae) Alliance. Ph.D. dissertation. University of Alaska.

Fraga, N. S. 2012. A revision of Erythranthe montioides and Erythranthe palmeri (Phrymaceae), with descriptions of five new species from California and Nevada, USA. Aliso 30: 49–68.

Nesom, G. L. 2011d. Recognition and synopsis of Mimulus sect. Tropanthus and sect. Leucocarpus (Phrymaceae). Phytoneuron 2011-28: 1–8.

Nesom, G. L. 2012g. Taxonomic summary of Erythranthe sect. Achlyopitheca (Phrymaceae). Phytoneuron 2012-42 1–4.

Nesom, G. L. 2012h. Taxonomy of Erythranthe sect. Mimulosma (Phrymaceae). Phytoneuron 2012-41: 1–36.

Nesom, G. L. 2012i. Taxonomy of Erythranthe sect. Simiola (Phrymaceae) in the USA and Mexico. Phytoneuron 2012-40: 1–123.

Nesom, G. L. 2014b. Taxonomy of Erythranthe sect. Erythranthe (Phrymaceae). Phytoneuron 2014-31: 1–41.

Nesom, G. L. 2017. Taxonomic review of the Erythranthe moschata complex (Phrymaceae). Phytoneuron 2017-17: 1–29.

Vickery, R. K. 1978. Case studies in the evolution of species complexes in Mimulus. Evol. Biol. 11: 404–506.

Whittall, J. B. et al. 2006. The Mimulus moschatus alliance (Phrymaceae): Molecular and morphological phylogenetics and their conservation implications. Syst. Bot. 31: 380–397.

Lower Taxa

Erythranthe acutidens, Erythranthe alsinoides, Erythranthe ampliata, Erythranthe androsacea, Erythranthe arenaria, Erythranthe arenicola, Erythranthe arvensis, Erythranthe barbata, Erythranthe bicolor, Erythranthe brachystylis, Erythranthe breviflora, Erythranthe breweri, Erythranthe caespitosa, Erythranthe calcicola, Erythranthe calciphila, Erythranthe cardinalis, Erythranthe carsonensis, Erythranthe charlestonensis, Erythranthe chinatiensis, Erythranthe cinnabarina, Erythranthe corallina, Erythranthe cordata, Erythranthe decora, Erythranthe dentata, Erythranthe diffusa, Erythranthe discolor, Erythranthe eastwoodiae, Erythranthe erubescens, Erythranthe exigua, Erythranthe filicaulis, Erythranthe filicifolia, Erythranthe floribunda, Erythranthe gemmipara, Erythranthe geniculata, Erythranthe geyeri, Erythranthe glaucescens, Erythranthe gracilipes, Erythranthe grandis, Erythranthe grayi, Erythranthe guttata, Erythranthe hallii, Erythranthe hardhamiae, Erythranthe hymenophylla, Erythranthe inamoena, Erythranthe inconspicua, Erythranthe inflatula, Erythranthe jungermannioides, Erythranthe laciniata, Erythranthe latidens, Erythranthe lewisii, Erythranthe linearifolia, Erythranthe marmorata, Erythranthe michiganensis, Erythranthe microphylla, Erythranthe minor, Erythranthe montioides, Erythranthe moschata, Erythranthe nasuta, Erythranthe norrisii, Erythranthe nudata, Erythranthe palmeri, Erythranthe pardalis, Erythranthe parishii, Erythranthe parvula, Erythranthe patula, Erythranthe percaulis, Erythranthe primuloides, Erythranthe ptilota, Erythranthe pulsiferae, Erythranthe purpurea, Erythranthe regni, Erythranthe rhodopetra, Erythranthe rubella, Erythranthe scouleri, Erythranthe shevockii, Erythranthe sierrae, Erythranthe suksdorfii, Erythranthe taylorii, Erythranthe thermalis, Erythranthe tilingii, Erythranthe trinitiensis, Erythranthe unimaculata, Erythranthe utahensis, Erythranthe verbenacea, Erythranthe washingtonensis, Erythranthe willisii

Key

1	Fruiting calyces inflated and sagittally compressed with abaxial lobes characteristically upcurving and closing throat or not; corollas yellow, often red-spotted; leaf blades palmately, sometimes subpinnately, veined.	> 2
2	Plants rhizomatous.	> 3
3	Corolla lobes fimbriate; stems procumbent; plants mat-forming.	> 4
4	Leaf blade surfaces villous-hirsute, hairs whitish, thickened, flattened, stiff, gland-tipped, fruiting calyces villous-hirsute, fruiting pedicels and distal stems stipitate-glandular; corollas: abaxial limbs spreading.	Erythranthe parvula
4	Leaf blade surfaces: abaxials glabrous, adaxials sometimes moderately villosulous, fruiting calyces glabrous or sparsely villosulous-glandular, hairs vitreous, flattened, eglandular or minutely gland-tipped, fruiting pedicels and stems glabrous; corollas: abaxial limbs strongly reflexed.	Erythranthe chinatiensis
3	Corolla lobes not fimbriate (entire or apically notched); stems decumbent, ascending, or erect to suberect, sometimes procumbent; plants not mat-forming.	> 5
5	Rhizomes prolifically produced, filiform.	> 6
6	Leaf blade surfaces hirtellous to softly hirsute.	Erythranthe corallina
6	Leaf blade surfaces glabrous, glabrate, pilose, villous, glandular-villous, or stipitate-glandular.	> 7
7	Flowers 6–16, from proximal to distal nodes; corolla tube-throats 10–15 mm; fruiting pedicels (25–)40–75 mm; stems usually erect, 20–50 cm.	Erythranthe utahensis
7	Flowers 1–3(–5), from distal nodes; corolla tube-throats 9–11 or 15–28 mm; fruiting pedicels 10–35(–40) mm; stems erect to erect-ascending, procumbent, or decumbent to decumbent-ascending, 2–35 cm.	> 8
8	Stems procumbent or decumbent to decumbent-ascending, 3–10 cm; plants forming matted colonies; leaf blades 3–12 mm, margins entire, mucronulate, or barely denticulate; corolla tube-throats 15–18 mm.	Erythranthe caespitosa
8	Stems erect to erect-ascending, 2–35 cm; plants solitary to colonial; leaf blades 5–35(–55) mm, margins shallowly dentate to denticulate; corolla tube-throats 9–11 mm or 15–28 mm.	> 9
9	Corolla tube-throats 15–28 mm, exserted 5–10 mm beyond calyx margin.	Erythranthe tilingii
9	Corolla tube-throats 9–11 mm, exserted 0–1(–2) mm beyond calyx margin.	Erythranthe minor
5	Rhizomes usually 1–few, usually broader than filiform.	> 10
10	Calyx throats not closing at maturity.	> 11
11	Corollas weakly bilabiate, tube-throats 6–8 mm, exserted 1–3 mm beyond calyx margin, limbs expanded 5–8 mm; flowers plesiogamous.	Erythranthe geyeri
11	Corollas strongly bilabiate, tube-throats 10–14 mm, exserted 5–8 mm beyond calyx margin, limbs expanded 10–15 mm; flowers herkogamous.	Erythranthe michiganensis
10	Calyx throats closing at maturity.	> 12
12	Leaf blades oblong-elliptic to oblong-lanceolate, usually 3–4 times longer than wide, bases attenuate, margins evenly, shallowly dentate or crenate to mucronate or mucronulate; plants glabrous.	Erythranthe scouleri
12	Leaf blades ovate to ovate-elliptic, broadly elliptic, suborbicular to broadly ovate-triangular or ovate-lanceolate, usually 1–2 times longer than wide, bases rounded, cuneate, subcordate, or truncate, margins dentate (E. decora) or crenate to dentate or toothed, rarely lobed or dissected; plants glabrate or hairy, rarely glabrous.	> 13
13	Leaf blades ovate-triangular to ovate-lanceolate, bases rounded to truncate to shallowly cuneate, palmately (3–)5–7-veined; corolla tube-throats 18–26 mm; stems minutely hirtellous, sometimes glabrate.	Erythranthe decora
13	Leaf blades ovate-elliptic to ovate or suborbicular, bases rounded, cuneate, truncate, or subcordate, usually subpinnately 5–7-veined; corolla tube-throats (10–)12–20 mm or (14–)16–24 mm; stems villous-glandular to hirtellous, hirsutulous, or pilose-hirsutulous.	> 14
14	Stems (6–)15–65(–80) cm; fruiting pedicels, fruiting calyces, and distal stems vestiture variable, not puberulent-glandular; corolla tube-throats (10–)12–20 mm, exserted 3–5 mm beyond calyx margin; fruiting calyces 11–17(–20) mm.	Erythranthe guttata
14	Stems (25–)50–120(–160) cm; fruiting pedicels, fruiting calyces, and distal stems densely puberulent, hairs a mix of crinkly and minutely stipitate-glandular; corolla tube-throats (14–)16–24 mm, exserted (8–)10–15 mm beyond calyx margin; fruiting calyces 15–22(–25) mm.	Erythranthe grandis
2	Plants fibrous-rooted or taprooted, without rhizomes or stolons (sometimes rooting at nodes).	> 15
15	Flowers herkogamous or plesiogamous, chasmogamous; corolla tube-throats (4–)7–23 mm, exserted (0–)3–8 mm (sometimes 1 mm in smallest corollas of E. microphylla) beyond fruiting calyx margin.	> 16
16	Stems moderately to densely villous-glandular, at least proximally.	> 17
17	Stems, leaves, and fruiting pedicels moderately to densely villous-glandular, without eglandular hairs, fruiting calyces densely hirtellous, sometimes sparsely stipitate-glandular, densely villous at sinuses; fruiting pedicels 15–45 mm; flowers herkogamous.	Erythranthe marmorata
17	Stems, leaves, fruiting pedicels, and fruiting calyces moderately villous-glandular with gland-tipped hairs, mixed hirtellous and stipitate-glandular, or moderately to densely stipitate-glandular, sometimes hirtellous-eglandular; fruiting pedicels 7–17 mm; flowers plesiogamous or herkogamous.	> 18
18	Corollas tube-throats 11–20 mm, exserted 4–8 mm beyond calyx margin; flowers herkogamous; coastal and near-coastal localities in Monterey, San Luis Obispo, and Santa Cruz counties, California.	Erythranthe arenicola
18	Corollas tube-throats 8–12 mm, exserted 1–2 mm beyond calyx margin; flowers plesiogamous; Yellowstone National Park, Wyoming.	Erythranthe thermalis
16	Stems delicately, sparsely stipitate-glandular, short villous-glandular, glabrous, or glabrate, sometimes hirtellous or distals puberulent-glandular.	> 19
19	Corollas pale yellow, palate dark yellow, drying blue-green; s Arizona, New Mexico.	Erythranthe unimaculata
19	Corollas, including palate, usually yellow, sometimes with a median splotch or red-spotted; British Columbia, California, Idaho, Nevada, Oregon, Washington.	> 20
20	Leaf blade margins bipinnately dissected, ca. 5–12(–15) primary divisions on each side.	Erythranthe filicifolia
20	Leaf blade margins entire or toothed to sometimes lobed at base.	> 21
21	Cauline leaf blades 5–15(–30) × 1–5 mm.	> 22
22	Cauline leaf blades 5–15(–30) mm; plants glabrous or stems, leaves, and fruiting calyces minutely stipitate-glandular, hairs 0.05–0.1 mm, at least just above nodes; fruiting calyces 6–13 mm; corollas without a large red splotch; Colusa, Glenn, Lake, Mendocino, Napa, and Sonoma counties, California.	Erythranthe nudata
22	Cauline leaf blades 7–10 mm; plants glabrous; fruiting calyces (4–)5–6 mm; corollas with a large red splotch at base of proximal middle lip; Plumas County, California.	Erythranthe percaulis
21	Cauline leaf blades (3–)10–50 × 3–25 mm.	> 23
23	Distal cauline leaf blades connate-perfoliate, disclike; stems and leaf surfaces glaucous.	Erythranthe glaucescens
23	Distal cauline leaves subclasping or narrowly perfoliate, not connate-perfoliate, not disclike; stems and leaf surfaces not glaucous.	> 24
24	Flowers usually from distal nodes; corolla tube-throats (6–)8–16(–20) mm, exserted (1–)2–6(–8) mm beyond calyx margin, limbs expanded 8–25 mm; stems and fruiting pedicels: distals hirtellous or mixed hirtellous and stipitate-glandular, sometimes only short villous-glandular, stems sometimes glabrous below inflorescence; British Columbia, California, Idaho, Nevada, Oregon, Washington.	Erythranthe microphylla
24	Flowers usually evenly distributed from proximal to distal nodes; corolla tube-throats 7–10(–12) mm, exserted 1–3 mm beyond calyx margin, limbs expanded 8–12 mm; stems and fruiting pedicels short, delicately stipitate-glandular, distals minutely puberulent-glandular; Amador, Calaveras, El Dorado, Placer, Tehama, and Tuolumne counties, California.	Erythranthe pardalis
15	Flowers plesiogamous, chasmogamous or cleistogamous; corolla tube-throats 4–14 mm, exserted 0–5 mm beyond fruiting calyx margin.	> 25
25	Flowers chasmogamous; corolla limbs expanded 2–14 mm, tube-throats 4–14 mm.	> 26
26	Distal leaves closely paired and auriculate-clasping; stems usually glabrous.	> 27
27	Flowers from remote distal nodes; stems glabrous, sometimes minutely hirtellous in inflorescence, hairs deflexed, eglandular; fruiting calyces (7–)9–14 mm; British Columbia, California, Idaho, Montana, Nevada, Oregon, Utah, Washington, Wyoming.	Erythranthe arvensis
27	Flowers from distal nodes or all nodes; stems glabrous or sparsely, minutely stipitate-glandular; fruiting calyces 7–18(–20) mm; Arizona, California, Colorado, Nevada, New Mexico, Texas, Utah.	> 28
28	Fruiting calyx throats not closing; flowers often produced from all nodes; stems, fruiting pedicels, and calyces glabrous or calyces minutely scabrous-hirtellous; fruiting calyces 7–11 mm; Texas.	Erythranthe inamoena
28	Fruiting calyx throats closing; flowers at distal nodes; stems, fruiting pedicels, and fruiting calyces sparsely stipitate-glandular; fruiting calyces (8–)14–18(–20) mm; Arizona, California, Colorado, Nevada, New Mexico, Texas, Utah.	Erythranthe cordata
26	Distal leaves not paired and not auriculate-clasping; stems glabrous or sparsely hirtellous and/or finely villosulous-glandular.	> 29
29	Calyx lobes usually 3 or 3 and 5 on same plant, if 5 then with 2 interpolated lobes much smaller than abaxial pair.	Erythranthe calciphila
29	Calyx lobes 5, ca. equal size or adaxial slightly longer.	> 30
30	Leaves as long as wide or wider than long, blades elliptic-ovate to broadly ovate, suborbicular, or depressed-ovate, margins irregularly dentate to dentate-serrate or nearly lacerate-dentate, commonly doubly toothed; plants commonly producing tiny cleistogamous flowers on branches separate from those with larger flowers; corolla tube-throats (5–)8–12 mm.	Erythranthe nasuta
30	Leaves longer than wide, blades elliptic to elliptic-obovate, oblanceolate, or oblong, margins narrowly pinnately lobed or dissected, sometimes merely shallowly toothed; plants producing flowers of only one size; corolla tube-throats 4–6 mm.	Erythranthe laciniata
25	Flowers cleistogamous; corolla limbs not or barely expanded or only 1–3 mm, tube-throats 4–12 mm.	> 31
31	Flowers and fruits subsessile; fruiting pedicels shorter than or equal to subtending leaves.	Erythranthe brachystylis
31	Flowers and fruits distinctly pedicellate; fruiting pedicels longer than subtending leaves.	> 32
32	Distal leaves: petioles 0 mm, blade surfaces glabrous, sometimes hirtellous; stems villous-glandular just above nodes, sometimes hirtellous distally; fruiting calyces with adaxial lobe usually distinctly longer than abaxial, slightly falcate.	Erythranthe nasuta
32	Distal leaves: petioles 0 mm or 1–4 mm, blade surfaces glabrous or villous on one or both surfaces; stems usually glabrous; fruiting calyces with adaxial lobe not distinctly longer than abaxial (except in E. regni), not falcate.	> 33
33	Fruiting calyces glabrous, (5–)7–10 mm.	> 34
34	Stems 15–45 cm, terete, sometimes becoming slightly fistulose; leaf blades 15–20(–50) × 15–25(–50) mm; fruiting pedicels 15–30 mm; corolla tube-throats 9–12 mm, exserted 3–5 mm beyond calyx margin; Arizona.	Erythranthe regni
34	Stems 2–8 cm, 4-angled; leaf blades 5–11 × 3–9 mm; fruiting pedicels 6–14 mm; corolla tube-throats 4–6 mm, exserted 0.5–1 mm beyond calyx margin; Colorado.	Erythranthe hallii
33	Fruiting calyces stipitate-glandular, hirtellous, or hirsutulous, sometimes sparsely glandular or mixed glandular-hirsutulous, (7–)9–18(–20) mm.	> 35
35	Fruiting calyces stipitate-glandular, (8–)14–18(–20) mm.	Erythranthe cordata
35	Fruiting calyces usually minutely hirtellous, (7–)9–14 mm.	> 36
36	Abaxial surfaces of distal and bracteal leaves densely villous, hairs long, sometimes vitreous, flattened, eglandular, multicellular; middle and distal cauline leaf blades depressed-ovate or broadly orbicular to nearly reniform; petioles 0 mm; stems, leaves, and fruiting calyces usually green; fruiting calyx throats closing or not, remaining open; stems erect to ascending; plants sometimes rooting at proximal cauline nodes if decumbent.	Erythranthe arvensis
36	Leaves glabrous, proximals sometimes sparsely villous; middle and distal cauline leaf blades ovate to ovate-lanceolate; petioles: distals 1–4 mm; stems, leaves, and fruiting calyces usually dark purplish; fruiting calyx throats closing; stems erect; plants not rooting at proximal nodes.	Erythranthe charlestonensis
1	Fruiting calyces not inflated and sagittally compressed, abaxial lobes not upcurving; corollas yellow, pink, red, crimson, magenta, lavender, or purple, rarely white; leaf blades palmately or pinnately veined.	> 37
37	Plants rhizomatous and/or stoloniferous, perennial.	> 38
38	Corollas red to purple or orange, rarely white; petioles 0 mm; blades: bases clasping to subclasping.	> 39
39	Stems scandent to pendent, stoloniferous; fruiting pedicels 10–30(–40) mm.	Erythranthe eastwoodiae
39	Stems erect to ascending or decumbent, rhizomatous, without stolons; fruiting pedicels (25–)30–120(–150) mm.	> 40
40	Corollas purple or light pink, rarely crimson, pale violet, white, pinkish white, yellowish white, or lavender; anthers included; leaf blade margins denticulate, subentire, or entire.	> 41
41	Corollas purple, rarely crimson, pale violet, white, pinkish white, yellowish white, or lavender; calyx tubes 12–15(–17) × 9–12 mm; widespread in nw North America.	Erythranthe lewisii
41	Corollas light pink; calyx tubes 14–19 × 6–8 mm; Sierra Nevada, California and Nevada.	Erythranthe erubescens
40	Corollas orange-red to scarlet, deep, dull, or red-orange, or crimson, rarely yellow or yellow-tinged; anthers exserted; leaf blade margins dentate to serrate.	> 42
42	Corolla tube-throats tubular, exserted 13–25 mm beyond calyx margin.	Erythranthe verbenacea
42	Corolla tube-throats funnelform or tubular, exserted 2–12 mm beyond calyx margin.	> 43
43	Leaf blade surfaces adaxially ± glandular-villous to glabrate on veins and lamina; fruiting calyces 17–28(–30) mm, lobes 4–7 mm, ovate to ovate-deltate, lobe apices attenuate-acute; corolla tube-throats (15–)20–30 mm; California, Nevada, Oregon, (5–)50–2300(–2800) m.	Erythranthe cardinalis
43	Leaf blade surfaces adaxially glabrous or minutely sessile- or stipitate-glandular along veins; fruiting calyces (27–)29–34 mm, lobes 7–10 mm, ovate, lobe apices abruptly attenuate to linear-caudate; corolla tube-throats 29–36 mm; Arizona, 2100–3300 m.	Erythranthe cinnabarina
38	Corollas yellow to orange-yellow, often red-spotted or -striped or brown-spotted; petioles 0 mm or 0.5–5(–20) mm; blades: bases subclasping to clasping or not clasping.	> 44
44	Stems with shortened internodes; leaves all basal or near basal (sometimes proximal cauline).	> 45
45	Leaf blades oblanceolate to elliptic-obovate; corollas densely hirsute on abaxial side of opening.	Erythranthe primuloides
45	Leaf blades linear to narrowly oblanceolate; corollas loosely hirsute on abaxial side of opening.	Erythranthe linearifolia
44	Stems with evident internodes; leaves cauline, basal usually not persistent.	> 46
46	Stems erect to erect-ascending, eglandular; corollas ± bilabiate.	Erythranthe dentata
46	Stems erect, ascending, or decumbent to procumbent or prostrate, glandular; corollas weakly bilabiate to nearly radially symmetric (strongly bilabiate in E. jungermannioides).	> 47
47	Calyx lobes 1–2 mm; anthers glabrous; styles scabrous; stolons forming overwintering turions; plants usually on cliff faces.	Erythranthe jungermannioides
47	Calyx lobes 2–9 mm; anthers glabrous or hairy; styles glabrous; stolons without turions; plants usually of habitats other than cliff faces.	> 48
48	Cauline leaf blades 30–70 mm; fruiting pedicels (15–)22–50 mm; calyx lobes 5–9 mm, linear-lanceolate to narrowly triangular.	Erythranthe ptilota
48	Cauline leaf blades 10–40(–50) mm; fruiting pedicels 4–25 mm; calyx lobes 2–4 mm, triangular to linear-lanceolate or narrowly triangular-acuminate.	> 49
49	Stems (2–)5–20 cm, usually erect, nodes 2–4(or 5); widely distributed.	Erythranthe moschata
49	Stems 7–45 cm, usually sprawling-decumbent, nodes (2–)4–15+; North Feather River, California.	Erythranthe willisii
37	Plants taprooted or fibrous-rooted, annual.	> 50
50	Leaves: petioles 0 mm, blades: bases subclasping to clasping.	> 51
51	Corollas bicolored (3 lobes of abaxial limbs yellow or medial lobe yellow and 2 lateral lobes maroon, 2 lobes of adaxial limbs maroon).	Erythranthe shevockii
51	Corollas not bicolored (lobes yellow, pinkish, or purple).	> 52
52	Corollas yellow.	Erythranthe carsonensis
52	Corollas white to light lavender, pinkish, rosy, or purplish.	> 53
53	Corollas white to lavender, pinkish, or rosy, palate and abaxial limb with or without small, reddish spots, yellow ridges present; corolla limbs not expanded.	Erythranthe parishii
53	Corollas pink to purple, palate and abaxial limb sometimes with yellow markings, yellow ridges absent; corolla limbs expanded 3–7 mm.	> 54
54	Corollas strongly bilabiate, adaxial lips darker than abaxials; corolla limbs expanded 7–10 mm.	Erythranthe purpurea
54	Corollas weakly bilabiate, adaxial lips not darker than abaxials; corolla limbs expanded 3–7 mm.	Erythranthe androsacea
50	Leaves: petioles 0 mm or to 30(–35) mm, blades: bases not clasping or subclasping.	> 55
55	Corollas light lavender to purple, abaxial lobes and palates with yellow patches, tube-throats 1.5–2.5 mm; stigmas persistent in fruit; capsules distinctly exserted.	Erythranthe exigua
55	Corollas yellow to pink, lavender, purple, magenta, red, or white, tube-throats 3–17 mm; stigmas not persistent; capsules included to slightly exserted.	> 56
56	Petioles 2–3 mm, laterally compressed, deeply saccate at base, usually containing a lenticular propagule.	Erythranthe gemmipara
56	Petioles 0–30 mm, not compressed, not saccate at base, not containing a lenticular propagule.	> 57
57	Fruiting calyx margins subtruncate, lobes reduced.	> 58
58	Fruiting calyx lobes: 1 usually slightly longer; corollas yellow, abaxial limbs with a large maroon splotch; stems glandular-puberulent; petioles 1–20(–30) mm.	Erythranthe alsinoides
58	Fruiting calyx lobes subequal; corollas pale pink to rose pink, rose red, rose purple, or purple to magenta, throat sometimes yellow, abaxial limbs without a large maroon splotch; stems glabrous; petioles 0–5 mm.	> 59
59	Corollas pale pink to rose pink or purple to magenta, throats sometimes yellow, tube-throats 5–9 mm, limbs expanded 5–6 mm; flowers plesiogamous; fruiting pedicels 5–15 mm.	Erythranthe inconspicua
59	Corollas rose red or pale pink to rose purple, throats sometimes yellow, tube-throats 8–12 mm, limbs expanded 7–12 mm; flowers herkogamous; fruiting pedicels 6–7 mm or 10–23 mm.	> 60
60	Fruiting pedicels 6–7 mm, shorter than subtending leaves.	Erythranthe grayi
60	Fruiting pedicels 10–23 mm, longer than subtending leaves.	Erythranthe acutidens
57	Fruiting calyx margins distinctly lobed, lobes pronounced.	> 61
61	Fruiting calyces strongly angled, ribs corky, lobes spreading.	> 62
62	Corollas yellow, adaxial lip white, sometimes yellow.	Erythranthe bicolor
62	Corollas pink to red, rose red, red-purple, purple, or lavender.	> 63
63	Corolla tube-throats 3–7 mm, throats usually light purple to lavender (similar in color to rest of corolla); fruiting pedicels 4–12 mm.	Erythranthe breweri
63	Corolla tube-throats 8–12(–17) mm, throats dark red-purple (darker than rest of corolla); fruiting pedicels 9–30 mm.	Erythranthe filicaulis
61	Fruiting calyces weakly or strongly angled, not corky, lobes erect.	> 64
64	Corollas pink, purple, yellow, rose lavender, or (in E. barbata and E. shevockii) bicolored dark maroon and yellow.	> 65
65	Calyx lobe margins ciliate.	> 66
66	Corollas: 2 adaxial lobes much reduced, smaller than 3 abaxials.	Erythranthe gracilipes
66	Corollas: abaxial and adaxial lobes ± same size.	> 67
67	Fruiting calyces becoming red-angled or red; corollas weakly bilabiate, limbs expanded 3–5 mm, lobes entire or weakly notched.	Erythranthe rubella
67	Fruiting calyces sometimes red-spotted on ribs, becoming straw colored; corollas strongly bilabiate, limbs expanded 5–17 mm, lobes deeply notched.	> 68
68	Fruiting calyces minutely glandular, sometimes red-spotted.	Erythranthe sierrae
68	Fruiting calyces glabrous, sometimes red-spotted on ribs, becoming straw colored.	Erythranthe palmeri
65	Calyx lobe margins glabrous.	> 69
69	Fruiting pedicels erect to ascending.	> 70
70	Corollas deep pink to purple, abaxial limbs with 2 yellow ridges, limbs expanded 7–15 mm.	Erythranthe discolor
70	Corollas pale pink to pink, palate with a broad yellow patch covering ridges and lateral areas, limbs expanded 16–25 mm.	Erythranthe rhodopetra
69	Fruiting pedicels ascending to often spreading horizontally.	> 71
71	Corollas bicolored (2 lobes of adaxial lips maroon, 3 lobes of abaxial limbs yellow or medial lobe yellow and 2 lateral lobes maroon).	Erythranthe barbata
71	Corollas not bicolored (lobes pinkish to purple).	> 72
72	Styles distally pubescent; stigmas distinctly shorter than corolla tubes.	Erythranthe diffusa
72	Styles glabrous; stigmas equal in length to corolla tubes or exserted.	Erythranthe hardhamiae
64	Corollas yellow or (in color morph of E. calcicola) white, sometimes pinkish or flesh colored.	> 73
73	Stems erect; leaves: blades linear to lanceolate, sometimes ovate or spatulate, 0.5–8(–10) mm wide, margins entire, rarely toothed, petioles 0(–2) mm.	> 74
74	Abaxial corolla limb with one large central red spot, if red spot absent then throat mottled red.	> 75
75	Corolla tube-throats 4–6 mm, indistinct from throat, palates glabrous or sparsely bearded.	Erythranthe suksdorfii
75	Corolla tube-throats (5–)7–11 mm, distinct from abruptly expanding throat, palates densely bearded.	Erythranthe carsonensis
74	Abaxial corolla limb red-spotted, but not with a single large red spot.	> 76
76	Corollas yellow, tube-throats funnelform, adaxial surfaces red-tinged.	Erythranthe discolor
76	Corollas yellow, white, or bicolored (abaxial limbs yellow with red spots, adaxials maroon-purple), tube-throats funnelform to cylindric, adaxial surfaces not red-tinged.	> 77
77	Corollas yellow or white, tube-throats 6–13 mm; calyx ribs strongly angled.	Erythranthe calcicola
77	Corollas yellow or bicolored (abaxial limbs yellow with red spots, adaxials maroon-purple), tube-throats (5–)6–15 mm; calyx ribs weak.	> 78
78	Corolla tube-throats cylindric to funnelform, lateral lobes entire or shallowly notched, palates glabrous or sparsely bearded; calyx margins ciliate.	Erythranthe montioides
78	Corolla tube-throats cylindric, lateral lobes 2-fid, palates bearded; calyx margins glabrous.	Erythranthe barbata
73	Stems prostrate to procumbent-trailing, decumbent, ascending, or erect; leaves: blades lanceolate to oblanceolate, elliptic, oblong, ovate, obovate, or deltate, (1–)2–30 mm wide, margins toothed, sometimes entire, petioles (0–)1–30 mm.	> 79
79	Cauline leaves: petioles 1–30(–35) mm, blades ovate, sometimes deltate, ovate-lanceolate, broadly lanceolate, elliptic-ovate, or triangular, palmately or pinnately veined, bases rounded to cuneate, truncate, or cordate.	> 80
80	Stems prostrate to ascending-erect, sharply bent at basal nodes; fruiting pedicels usually closely paired.	Erythranthe hymenophylla
80	Stems erect to prostrate, decumbent, or ascending, straight (if erect) or geniculate at nodes; fruiting pedicels not paired.	> 81
81	Stems and pedicels villous or villous-glandular, pedicels sometimes stipitate-glandular, hairs 0.5–1.2(–2) mm; leaf blades pinnately to subpinnately veined, sometimes ± palmately veined.	> 82
82	Stems erect to ascending; fruiting calyces greenish; styles hispid-hirtellous; Oregon.	Erythranthe washingtonensis
82	Stems erect to prostrate, decumbent, or ascending; fruiting calyces usually red-spotted; styles glabrous; widespread.	> 83
83	Corolla tube-throats (4–)5–10 mm, limbs expanded 3–4 mm diam.; flowers plesiogamous.	Erythranthe floribunda
83	Corolla tube-throats 9–12 mm, limbs expanded 10–18 mm diam.; flowers herkogamous.	Erythranthe geniculata
81	Stems and fruiting pedicels stipitate-glandular, sometimes puberulent-glandular to villous-glandular, hairs 0.05–0.5 mm; leaf blades palmately veined.	> 84
84	Corolla tube-throats 8–12(–14) mm.	> 85
85	Stems moderately puberulent-glandular to villous-glandular, hairs 0.1–0.8 mm, flattened, vitreous, leaves moderately puberulent-glandular to villous-glandular, fruiting calyces densely stipitate-glandular; stems terete; styles hispid-hirtellous.	Erythranthe washingtonensis
85	Stems and leaves sparsely sessile- to subsessile-glandular, hairs 0.05–0.2 mm, fruiting calyces sparsely stipitate-glandular or glabrous; stems 4-angled; styles glabrous.	Erythranthe ampliata
84	Corolla tube-throats 5–8 mm.	> 86
86	Petioles (5–)8–25 mm; blades 4–12(–17) mm; fruiting pedicels 10–25(–38) mm; fruiting calyces 5–6(–7) mm, sparsely stipitate-glandular to sparsely hirtellous; corolla tube-throats 7–8 mm.	Erythranthe patula
86	Petioles 3–5(–8) mm; blades 4–20 mm; fruiting pedicels 6–13 mm; fruiting calyces 4–5 mm, densely invested with tiny, waxy-white, eglandular, papillose hairs between angles; corolla tube-throats 5–7 mm.	Erythranthe taylorii
79	Cauline leaves: petioles 0 mm or 1–10(–15) mm, blades elliptic to oblong, lanceolate, oblanceolate, ovate, or obovate, palmately 3–5-veined, sometimes 1-veined, subpalmately veined, or with 1–3 distal vein pairs diverging pinnately, bases attenuate, sometimes cuneate, obtuse, rounded, subauriculate, truncate, or cordate.	> 87
87	Stems villous-glandular, hairs 0.2–1(–1.5) mm.	> 88
88	Midcauline leaves: petioles 1–12 mm; corolla tube-throats (4–)5–10 mm.	Erythranthe floribunda
88	Midcauline leaves: petioles 0 mm or 1–10(–15) mm; corolla tube-throats 9–16 mm.	> 89
89	Midcauline leaves: petioles 0 mm or proximals 1–3(–5) mm; corollas red-dotted but without discrete red splotches or white patches, tube-throats 9–12(–14) mm; fruiting calyces: ribs angled, lobes erect.	Erythranthe arenaria
89	Midcauline leaves: petioles 5–10(–15) mm; corollas: base of each lobe with a prominent maroon blotch, abaxial limbs with white patch at 2 sinus bases, tube-throats 12–16 mm; fruiting calyces: ribs rounded-thickened, lobes often incurved.	Erythranthe norrisii
87	Stems sessile-glandular, minutely stipitate-glandular, or puberulent, sometimes minutely hirtellous, hairs 0.1–0.3 mm.	> 90
90	Petioles 2–9 mm; fruiting pedicels divergent-arcuate.	> 91
91	Leaves basal and cauline; petioles 2–9 mm, distinctly 3-veined, winged; fruiting pedicels 12–38 mm; tube-throats, lobes, and palate ridges yellow.	Erythranthe pulsiferae
91	Leaves usually cauline; petioles 4–8 mm, 1-veined, not winged; fruiting pedicels 9–17 mm; tube-throats yellow, lobes (limbs) pink or white with pink distal borders, palate ridges yellow.	Erythranthe trinitiensis
90	Petioles 0 mm or 1–3 mm; fruiting pedicels straight.	> 92
92	Fruiting calyces 8–12 mm, short stipitate-glandular or sessile-glandular; fruiting pedicels 11–28 mm; leaves basal and cauline.	Erythranthe latidens
92	Fruiting calyces 5–11 mm, sparsely, minutely hirtellous, eglandular, sometimes sparsely sessile-glandular; fruiting pedicels 5–11 mm or 7–18 mm; leaves usually cauline, basal usually deciduous by flowering.	> 93
93	Fruiting calyces 5–6 mm; fruiting pedicels 5–11 mm; corolla tube-throats 3.5–5 mm, not exserted beyond calyx margins; distal leaves: petioles 1–3 mm.	Erythranthe breviflora
93	Fruiting calyces 7–11 mm; fruiting pedicels 7–18 mm; corolla tube-throats 5–8 mm, exserted 1–3 mm beyond calyx margins; distals leaves: petioles 0 mm.	Erythranthe inflatula