Clearwater National Forest |
Spacious monkeyflower Mimulus ampliatus Grant STATUS USFS Region 1: Sensitive USFWS: none ICDC: G1/S1 INPS: GP1 TAXONOMY Family: Scrophulariaceae Common Name: spacious monkeyflower Description Mimulus ampliatus is a slender annual in the snapdragon family (Scrophulariaceae), 4-20 cm tall, with sticky glandular foliage and yellow flowers. The leaves are 6-14 mm long with slightly toothed margins and palmate venation. Flowers are less than 1 inch long; the lower lip of the corolla is strongly reflexed from the upper and usually bears some reddish-brown dots. The tubular portion of the flower is hairy at its entrance (throat). The glandular-puberulent calyx is 4.5-8 mm long, with teeth of equal length (Hitchcock 1959, Lichthardt 1999). Distinguishing Features and Similar Species The annual life-form, glandular stems, regular calyx (lobes all equal), and petioles shorter than the leaf blades, are diagnostic. The glabrous (non-hairy) style differentiates M. ampliatus from the very similar M. washingtonensis , which has hairy styles and is copiously and minutely hairy on the stem, whereas M. ampliatus has sparse, longer stem hairs. The ranges of the two species do not overlap. DISTRIBUTION Range M. ampliatus is endemic to Idaho, where it is known from six widely scattered locations in Lewis, Nez Perce, Idaho and Clearwater Counties. It is suspected to occur in Latah County. Habitat Spacious monkeyflower occurs in open grassland sites and forest openings. Plants grow in microsites with enhanced spring moisture or shade. One site is a moist meadow, the others on seepy rock outcrops. Known locations range from 2,600 to 6,900 ft. on volcanics as well as granite (Lichthardt 1999). REMARKS In Flora of the Pacific Northwest, M. ampliatus is treated as a subspecies of M. washingtonensis. The older published species name, M. ampliatus, was resurrected by Robert Meinke of Oregon State University based on additional specimens. This species probably occurs at more sites than initially expected. Small yellow monkeyflowers are difficult to key out and the revised key by Meinke is just now coming into wide use. It is probable that it has been collected in the past and keyed out under M. washingtonensis, M. floribundus or others. Because the species is found in moist openings, often on steep balds, there is little chance for conflict with timber harvest. The only impacts likely to occur with this species would be livestock use and weed invasion. It generally is found on mineral soil in the openings or sometimes on road cuts. These areas do not support an abundance of grass so it is unlikely the plant will be grazed, but it could be trampled. More populations need to be found before the status and ecology of this species can be more fully understood. REFERENCES Hitchcock, C. L., A. Cronquist, M. Ownbey and J.S. Thompson. 1959. Vascular Plants of the Pacific Northwest, part 4. University of Washington Press, Seattle, WA. Lichthardt, J.J. 1999. Action plant for sensitive plant species on the Clearwater National Forest. Report to the Clearwater National Forest SO, Orofino, ID. Idaho Dept. of Fish and Game, Conservation Data Center, Boise, ID. 17 pages plus appendices.
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