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Bentham's monkeyflower, small-leaf monkey-flower

many-flower monkey-flower, purple-stem monkey-flower

Habit Annuals, fibrous-rooted. Annuals, fibrous-rooted or filiform-taprooted.
Stems

erect, simple, sometimes many-branched from basal cauline nodes, terete, sometimes distinctly 4-angled, (3–)5–30(–45) cm, glabrous below inflorescence, sometimes distals hirtellous, hairs commonly deflexed, or mixed hirtellous and stipitate-glandular, sometimes only short villous-glandular, hairs gland-tipped.

erect to decumbent, sometimes procumbent-trailing, straight or geniculate at nodes, simple or many-branched, 3–22(–40) cm, villous-glandular, hairs greatly variable in length and density, gland-tipped, sometimes 0.2–0.5 mm, sparsely stipitate-glandular.

Leaves

basal and cauline, basal sometimes absent at flowering;

petiole: basal or proximals to medials 3–25(–35) mm, distals 0 mm (then blade subclasping to narrowly perfoliate);

blade often purplish, palmately 3–5-veined, ovate or ovate-lanceolate to elliptic-ovate, suborbicular, or depressed-ovate, (3–)10–35 × 3–25 mm, base rounded to truncate or subcordate, margins shallowly crenate to sharply crenate-serrate, teeth 5–10 per side, basal and proximal often irregularly incised near petiole and sublyrate, apex acute to obtuse-rounded, surfaces glabrous or sparsely to moderately hirtellous, eglandular.

cauline, basal mostly deciduous by flowering;

petiole 1–12 mm;

blade pinnately to subpalmately veined, ovate, (3–)8–25(–35) × (1–)5–18(–26) mm, base cuneate to truncate or cordate, margins serrate to sparsely dentate, apex acute, surfaces villous-glandular, hairs greatly variable in length and density, gland-tipped, sometimes 0.2–0.5 mm, sparsely stipitate-glandular.

Flowers

herkogamous, 1–8(–14), usually from distal nodes, chasmogamous.

plesiogamous, 1–20, from proximal to distal nodes.

Styles

sparsely hirtellous.

glabrous.

Corollas

yellow to golden yellow or orangish yellow, usually red-spotted, abaxial limb sometimes with a large red splotch, bilaterally symmetric, bilabiate;

tube-throat broadly funnelform, (6–)8–16(–20) mm, exserted (1–)2–6(–8) mm beyond calyx margin;

limb expanded 8–25 mm, palate villous.

yellow, abaxial limb red-dotted, bilaterally symmetric, weakly bilabiate;

tube-throat funnelform-cylindric, (4–)5–10 mm, exserted slightly beyond calyx margin or not;

limb expanded 3–4 mm diam., lobes usually oblong, apex notched.

Fruiting pedicels

8–30(–50) mm, distals hirtellous, hairs commonly deflexed, or mixed hirtellous and stipitate-glandular, sometimes only short villous-glandular, hairs gland-tipped.

5–20(–26) mm, villous-glandular, hairs greatly variable in length and density, gland-tipped, sometimes 0.2–0.5 mm, sparsely stipitate-glandular.

Fruiting calyces

nodding 30–90º, sometimes red-tinged or -dotted, ovoid-campanulate to broadly cylindric-campanulate, inflated, sagittally compressed, (7–)9–16(–20) mm, minutely hirtellous, hairs sometimes reduced to basal cells, or glabrous, throat strongly to weakly closing.

greenish or purplish to red-dotted, cylindric, ± inflated, 4–7 mm, margins distinctly toothed or lobed, villous-glandular, lobes pronounced, erect.

Capsules

included, 6–9(–11) mm.

included, 4–7 mm.

Anthers

included, glabrous.

included, glabrous.

2n

= 28, 56.

= 32.

Erythranthe microphylla

Erythranthe floribunda

Phenology Flowering Mar–Jul. Flowering (May–)Jun–Aug(–Sep).
Habitat Rock depressions, rocky ridges, cliff faces, roadcuts, wet meadows, seeps, stream banks, drying ponds, ephemeral stream channels, vernal springs over serpentine, roadsides and roadside ditches, dry banks, lava soils, loam, clay, gravel, yellow pine, oak-pine, mixed oak woodlands, oak-chaparral. Under overhangs, moist roofs of caves, wet rock crevices, cliff faces, wet cliff bases, below waterfalls, seeps, springs, humus and moist soils over rocks and slabs, moist slopes, ditches and pond edges, wet edges of creeks and rivers, drying mud on margins of wetland depressions, creek beds, wet or swampy meadows, along trails, in lodgepole pine, ponderosa pine, ponderosa pine-Douglas fir, and spruce-fir woodlands.
Elevation 20–1700(–2600) m. (100–5600(–8500) ft.) (100–)1800–2600(–3100) m. ((300–)5900–8500(–10200) ft.)
Distribution
from FNA
CA; ID; NV; OR; WA; BC
[WildflowerSearch map]
from FNA
AR; AZ; CA; CO; ID; MT; NM; NV; OR; SD; UT; WA; WY; AB; BC; Mexico (Baja California, Baja California Sur, Chihuahua, Sinaloa, Sonora)
[WildflowerSearch map]
Discussion

Erythranthe microphylla is characterized by its annual duration (fibrous-rooted), usually simple stems, relatively widely spaced leaves, glabrous or hirtellous vestiture, open corollas, and calyces closing at the throat. Even in the smallest corollas, the stigma is positioned above the adaxial anther pair, indicating that all are primarily allogamous. Some plants have basal and proximal cauline leaves with exaggeratedly and irregularly toothed-incised margins (especially in Lake and Napa counties, California, as in the types of Mimulus glareosus and M. guttatus var. insignis, respectively), but a similar tendency can be seen over most of the geographic range. Plants of E. microphylla vary greatly in height, leaf size, and flower size (the larger flowers approaching the size of those in E. grandis and E. decora), yet all seem to be within the expression of a single species.

An inversion sequence of chromosome 8 (the DIV1 region) is perfectly correlated with the life history features of at least four species of sect. Simiolus (D. B. Lowry and J. H. Willis 2010). One sequence occurs in Erythranthe guttata and E. grandis, which are perennial and rhizomatous, occur in habitats with year-round moisture, and flower relatively late in the season, while the opposite sequence occurs in E. nasuta and E. microphylla, which are annual and slender-taprooted or fibrous-rooted, occur in quickly drying habitats, and flower in early season. The inversion, with its tightly linked, locally adaptive alleles, contributes to isolating mechanisms between species with contrasting sequences and preserves the constellation of features that makes each a recognizable entity.

Hybridization and apparent introgression occur among Erythranthe guttata, E. microphylla, and E. nasuta, yet each remains distinct in duration, perennating morphology, and habit. Erythranthe arvensis (annual) also is a member of this gene-sharing group. A whole-genome analysis by A. D. Twyford and J. Friedman (2015) showed that populations of E. guttata and E. microphylla cluster together within each of several geographically delimited regions; they interpreted their trees as showing phylogenetic relationships and concluded that E. guttata and E. microphylla are conspecific. Other evidence (G. L. Nesom 2014c, 2014d), particularly the DIV1 inversion sequence, indicates that E. guttata and E. grandis are most closely related to each other and were derived from an ancestor of annual duration. Thus, E. microphylla and E. nasuta are morphologically and phylogenetically distinct from E. guttata, despite extensive gene flow where they are sympatric with it.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Some plants identified here as Erythranthe floribunda in Arizona and southwestern New Mexico are distinctive in their prominently inflated calyces, sessile to subsessile leaves with attenuate bases and palmately three- to five-veined venation, and much-elongated pedicels (20–43 mm); numerous intermediates in Arizona make it difficult to conclude that the variants represent an entity discontinuous from plants of typical morphology. The variant morphology has not been observed among Mexican populations. Further discussion of this situation was given by G. L. Nesom (2012h).

Erythranthe floribunda has been documented from 12 counties in northern Arkansas (Carroll, Cleburne, Crawford, Franklin, Izard, Johnson, Logan, Newton, Pope, Searcy, Stone, and Washington), where it occurs at 300–500 m. The unpublished name Mimulus floribundus subsp. moorei Iltis appears in various checklists in reference to the Arkansas plants, but there appears to be no basis for treating them as distinct from the rest of the species. Elsewhere in the main range (western states), scattered variants extremely reduced in size, leaves, flowers, and overall stature appear to be at the lower limits of the species rather than taxonomically distinct.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 17, p. 415. FNA vol. 17, p. 404.
Parent taxa Phrymaceae > Erythranthe Phrymaceae > Erythranthe
Sibling taxa
E. acutidens, E. alsinoides, E. ampliata, E. androsacea, E. arenaria, E. arenicola, E. arvensis, E. barbata, E. bicolor, E. brachystylis, E. breviflora, E. breweri, E. caespitosa, E. calcicola, E. calciphila, E. cardinalis, E. carsonensis, E. charlestonensis, E. chinatiensis, E. cinnabarina, E. corallina, E. cordata, E. decora, E. dentata, E. diffusa, E. discolor, E. eastwoodiae, E. erubescens, E. exigua, E. filicaulis, E. filicifolia, E. floribunda, E. gemmipara, E. geniculata, E. geyeri, E. glaucescens, E. gracilipes, E. grandis, E. grayi, E. guttata, E. hallii, E. hardhamiae, E. hymenophylla, E. inamoena, E. inconspicua, E. inflatula, E. jungermannioides, E. laciniata, E. latidens, E. lewisii, E. linearifolia, E. marmorata, E. michiganensis, E. minor, E. montioides, E. moschata, E. nasuta, E. norrisii, E. nudata, E. palmeri, E. pardalis, E. parishii, E. parvula, E. patula, E. percaulis, E. primuloides, E. ptilota, E. pulsiferae, E. purpurea, E. regni, E. rhodopetra, E. rubella, E. scouleri, E. shevockii, E. sierrae, E. suksdorfii, E. taylorii, E. thermalis, E. tilingii, E. trinitiensis, E. unimaculata, E. utahensis, E. verbenacea, E. washingtonensis, E. willisii
E. acutidens, E. alsinoides, E. ampliata, E. androsacea, E. arenaria, E. arenicola, E. arvensis, E. barbata, E. bicolor, E. brachystylis, E. breviflora, E. breweri, E. caespitosa, E. calcicola, E. calciphila, E. cardinalis, E. carsonensis, E. charlestonensis, E. chinatiensis, E. cinnabarina, E. corallina, E. cordata, E. decora, E. dentata, E. diffusa, E. discolor, E. eastwoodiae, E. erubescens, E. exigua, E. filicaulis, E. filicifolia, E. gemmipara, E. geniculata, E. geyeri, E. glaucescens, E. gracilipes, E. grandis, E. grayi, E. guttata, E. hallii, E. hardhamiae, E. hymenophylla, E. inamoena, E. inconspicua, E. inflatula, E. jungermannioides, E. laciniata, E. latidens, E. lewisii, E. linearifolia, E. marmorata, E. michiganensis, E. microphylla, E. minor, E. montioides, E. moschata, E. nasuta, E. norrisii, E. nudata, E. palmeri, E. pardalis, E. parishii, E. parvula, E. patula, E. percaulis, E. primuloides, E. ptilota, E. pulsiferae, E. purpurea, E. regni, E. rhodopetra, E. rubella, E. scouleri, E. shevockii, E. sierrae, E. suksdorfii, E. taylorii, E. thermalis, E. tilingii, E. trinitiensis, E. unimaculata, E. utahensis, E. verbenacea, E. washingtonensis, E. willisii
Synonyms Mimulus microphyllus, M. glareosus, M. guttatus var. depauperatus, M. guttatus var. insignis, M. guttatus var. microphyllus, M. guttatus var. platycalyx, M. langsdorffii var. insignis, M. langsdorffii var. microphyllus, M. luteus var. depauperatus, M. nasutus var. insignis, M. platycalyx Mimulus floribundus, M. deltoideus, M. floribundus var. membranaceus, M. membranaceus, M. peduncularis, M. serotinus
Name authority (Bentham) G. L. Nesom: Phytoneuron 2012-39: 44. (2012) (Lindley) G. L. Nesom: Phytoneuron 2012-39: 38. (2012)
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