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Mimulus alsinoides Dougl. Ex. Benth.

Chickweed Monkeyflower

Scrophulariaceae (Figwort family)

General Description: A slender, simple or freely branched, glandular to partly glabrous annual 4-30 cm tall. Leaves are only 0.5-2 cm long, thin, and evidently to obscurely toothed. The three upper teeth of the calyx are acute and very short, while the lower two teeth are somewhat longer and rounded. The yellow flowers are strongly bilabiate and 8-14 mm in size. The central lobe of the lower lip is longer than the others and obviously deflexed. A prominent reddish-brown blotch occurs at the base of the lower lip.

Illustration.

Field Identification Tips: The yellow, strongly bilabiate flowers are over 8 mm and have a prominent reddish-brown blotch on the lower lip.

Phenology: Flowers April to June.

Similar Species: Mimulus guttatus is our most common yellow-flowered monkeyflower. It is variable in size, but in many cases is taller and with larger leaves and flowers than M. alsinoides. Furthermore, its upper calyx tooth is much larger than all the other teeth, a character that readily distinguishes it from M. alsinoides. The annual habit of M. alsinoides separates it from most other yellow-flowered monkeyflowers in Idaho, which are perennials. The range of the rare M. ampliatus is not known to overlap that of M. alsinoides. It is a small, yellow-flowered annual, but has a pubescent corolla with fine red dot markings to help distinguish it.

Habitat: Moist, shady places, especially in moss mats on cliffs.

Global Distribution: The main part of its range is in and west of the Cascade Mountains from southern British Columbia, south to northern California. Disjunct populations occur in north-central Idaho.

Idaho Distribution: Known from the St. Joe River drainage at Black Prince Creek in Shoshone County, and the North Forth Clearwater River drainage in Clearwater County, from near Canyon, upstream to the Aquarius area.