And right on schedule, as it was first reported by Lewis and Clark on August 12, 1805.
From the Forest Service website, a little background and a link: http://www.fs.fed.us/wildflowers/plant-of-the-week/mimulus_lewisii.shtml
Based on their journals, the explorers encountered Mimulus lewisii “on the head springs of the Missouri [River], at the foot of Portage hill” a site that is interpreted by Phillips as the head of Trail Creek, Montana, just below Lemhi Pass.
Lewis’s monkeyflower is a tall perennial forb, reaching a height of 3½ feet. It occurs commonly along mountain streamsides, often among rocks and boulders, from southeastern Alaska to Alberta and south to California, Utah, and Colorado. The opposite leaves are distinctive in being sessile, coarsely toothed, and having prominent palmate veins. The flowers have 5 petals fused at the base into a short tube and flaring at the mouth into two weakly-defined lips. To Linnaeus, these lips had the appearance of a smile or grin, earning the genus its name Mimulus after mimus for a grinning comic actor. The “smiling corolla” may also account for the common name of monkeyflower, for its fanciful resemblance to a grinning simian.
In any event, it’s a beautiful plant. This charmer was found near Arrowrock Reservoir, on a sand slide of decomposed granite.
This beauty was first reported by the Corps of Discovery on August 12, 1805, at Lemhi Pass, Montana.