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little redstem monkeyflower, red stem himulus, redstem monkeyflower, redstem or little redstem monkeyflower

Yellowstone monkeyflower

Habit Annuals, taprooted. Annuals, taprooted, rarely with a basal, runnerlike stem.
Stems

erect, simple, sometimes branched from basal nodes, 3–32 cm, minutely puberulent.

erect, simple or branched from basal nodes, 1.5–10(–15) cm, villous-glandular proximally, moderately to densely stipitate-glandular, sometimes hirtellous and eglandular distally.

Leaves

cauline, basal not persistent;

petiole 0 mm;

blade palmately 3-veined (in broader ones), linear to elliptic, 5–22(–30) × 1–5 mm, base narrowed, margins entire, sometimes toothed, apex acute to obtuse, surfaces minutely puberulent.

basal and cauline, cauline 2–5 pairs;

petiole: basal and proximal cauline 3–20 mm, distals 0 mm;

blade palmately 3–5-veined, suborbicular to ovate, depressed-ovate, ovate-deltate, or reniform, 4–15(–20) × 4–20 mm, base cuneate to truncate or subcordate, margins evenly crenate-dentate to subentire, apex acute to obtuse or rounded, surfaces moderately to densely stipitate-glandular, sometimes hirtellous and eglandular.

Flowers

herkogamous, sometimes plesiogamous, 1–106, from distal or medial to distal nodes.

plesiogamous, 1–5(–9), usually at distal nodes, chasmogamous.

Styles

glabrous.

hirtellous.

Corollas

yellow and abaxial limb and throat red dotted or pink to purple and throat yellow, bilaterally symmetric, weakly bilabiate;

tube-throat cylindric, 4–10 mm, exserted beyond calyx margin;

limb expanded 3–5 mm, lobes entire or weakly notched, abaxial limb glabrous.

yellow, red-dotted or not, bilaterally symmetric, strongly bilabiate;

tube-throat funnelform, 8–12 mm, exserted 1–2 mm beyond calyx margin;

limb expanded 12–15 mm, throat open, palate villous.

Fruiting pedicels

2–18 mm.

7–12 mm, moderately to densely stipitate-glandular, sometimes hirtellous and eglandular.

Fruiting calyces

becoming red-angled or red, campanulate to nearly cylindric, 4–9 mm, margins distinctly toothed or lobed, glabrous or minutely puberulent, ribs thickened, lobes pronounced, erect, margins ciliate.

ovate-campanulate, inflated, sagittally compressed, 8–11 mm, moderately to densely stipitate-glandular, sometimes hirtellous and eglandular, throat closing, adaxial lobe longer than others.

Capsules

included, 3–8 mm.

included, 5–6 mm.

Anthers

included, glabrous.

included, glabrous.

2n

= 28.

Erythranthe rubella

Erythranthe thermalis

Phenology Flowering Apr–Jun. Flowering Mar–Aug.
Habitat Open slopes and washes. Hot, shallow, quick-drying soils around thermal pools and vents.
Elevation 300–3000 m. [1000–9800 ft.] 2200–2600 m. [7200–8500 ft.]
Distribution
from FNA
AZ; CA; CO; NM; NV; TX; UT; WY; Mexico (Baja California, Sonora)
[WildflowerSearch map]
from FNA
WY
Discussion

Erythranthe thermalis is endemic to Yellowstone National Park in northwestern Wyoming. The species is recognized by its annual duration (without rhizomes), reduced stature and leaf size, and short, but broad-limbed, corollas with autogamous fertilization. Typical E. guttata (rhizomatous, herkogamous) also grows in the immediately surrounding areas but apparently not in hot soils. Each species maintains distinctions in growth form, phenology and mating system in common garden experiments (Y. Lekberg et al. 2012).

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

Source FNA vol. 17, p. 384. Treatment authors: Guy L. Nesom, Naomi S. Fraga. FNA vol. 17, p. 413. Treatment authors: Guy L. Nesom, Naomi S. Fraga.
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. 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. 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. veronicifolia
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. 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. tilingii, E. trinitiensis, E. unimaculata, E. utahensis, E. verbenacea, E. washingtonensis, E. willisii, E. veronicifolia
Synonyms Mimulus rubellus, M. gratioloides Mimulus thermalis
Name authority (A. Gray) N. S. Fraga: Phytoneuron 2012-39: 35. (2012) (A. Nelson) G. L. Nesom: Phytoneuron 2012-39: 44. (2012)
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