Erythranthe arvensis
field monkey-flower

Distribution: Occurring east of the Cascades crest in Washington; southern British Columbia to California, east to southern Idaho, Utah, and Nevada, disjunct in west-central Montana.

Habitat: Open slopes and stream bank.;

Flowers: May-July

Origin: Native

Growth Duration: Annual

Conservation Status: Not of concern


Annuals with fibrous roots or taproots, sometimes rooting at nodes near base if decumbent; stems 5-70 cm, erect to decumbent-ascending, unbranched or branching at medial to proximal nodes, generally with 4 angles, hollow or very narrow, glabrous, sometimes with coarse and stiff pubescence in inflorescence, hairs without glands bending backwards.


Leaves basal and cauline, or basal leaves may not persist, mid-stem or higher leaves often largest and becoming smaller distally; petiolate, petioles 3-20, distally sessile; blade ovate to orbicular to oblong, middle and distal cauline leaves may be orbicular to nearly reniform, generally 10-35 mm long and 6 to 26 broad, 3-5 palmately-arranged veins, earlobe-like appendages near base, base rounded to truncate to slightly cordate, margins distinctly toothed to nearly entire, larger plants show lower leaves lacerate lobed to pinnatifid margin bases, apex rounded, surfaces glabrous except bracts densely villous beneath and occasionally above, long eglandular hairs flattened and sometimes transparent.


Axillary flowers generally 3-8, emerging from distal-most nodes; fruiting pedicels eglandular and smooth, longer than subtending leaves, typically 5-40 mm; calyx sometimes with red dots, ovate to campanulate, inflated, compressed along sagittal plane, 9-14 mm, slightly hirtellous, throat sometimes closed or open, lobes curving upward weakly, top lobe not significantly longer than lower lobe, not distinctly curved; corollas yellow, commonly with red spots, weak bilateral symmetry or near radial symmetry, slightly bilabiate or almost regular; tube-throat cylindric to funnel-shaped, 8-12 mm, protruding 1-2 mm past calyx margin; limb expanded 5-10 mm; styles glabrous; anthers not protruding, glabrous.


Capsules 6-7 mm, included, stalked.

Accepted Name:
Erythranthe arvensis (Greene) G.L. Nesom
Publication: Phytoneuron 2012–39: 43. 2012.

Synonyms & Misapplications:
Mimulus arvensis Greene
Additional Resources:

PNW Herbaria: Specimen records of Erythranthe arvensis in the Consortium of Pacific Northwest Herbaria database

WA Flora Checklist: Erythranthe arvensis checklist entry

OregonFlora: Erythranthe arvensis information

E-Flora BC: Erythranthe arvensis atlas page

CalPhotos: Erythranthe arvensis photos

12 photographs:
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