The photo above shows a close-up of the flower of small-flowered prairie star as seen from rocky slopes high to the north of the day use area at Cottonwood Canyon State Park, Sherman County, Oregon........March 18, 2016. Two characteristics to note in the photo, a) the 3-lobed petals and the long, tapering calyx with a v-shaped base, about twice as long as wide.
The USDA PLANTS Database currently has this species named as Lithophragma parviflorum.
Also known as small-flowered fringe-cup, small-flowered prairie star is an attractive perennial with erect stems from 10-55 cm tall arising from clusters of cleft basal leaves. The herbage is often densely glandular-pubescent and commonly purple or reddish above. The basal leaves are moderately to abundantly haired, especially on the lower surface. The petioles of the basal leaves are 1-8 cm long, with the blades 1-5 cm wide. The blades are cleft, often nearly to the middle into 3-5 divisions which are further cleft into several smaller divisions. The 1-3 stem leaves usually have narrower leaf segments (See photo below.), with the upper leaf nearly sessile. The axils of all the leaves lack bulblets.
The inflorescence is at first crowded at the top of the stem, but elongates into a raceme as much as 15 cm long and 5-11 flowered. The pedicels are 2-8 mm long. The calyx, which is 7-12 mm long, is wide at its throat, but tapers gradually to the stem (This is an easy way to distinguish it from other northwest prairie stars. (See photo at right.). Each of the 5 calyx lobes are up to 2 m long. The 5 petals are white to pink, usually slightly unequal, and from 5-12 mm long. The individual petals are cleft 3-5 times, giving the petals a tattered appearance. The middle lobe of each petal is the longest. The stamens do not exceed the calyx.
Small-flowered prairie star is an interesting perennial wildflower for the spring rock garden or prairie garden. It looks good amongst basalt rock outcrops as well as bunchgrasses. It tends to bloom 2-3 weeks later than both smooth and bulblet prairie star.
Small-flowered prairie star may be found on open, grassy to sagebrush covered slopes, and in open, low altitude forests.
Small-flowered prairie star may be found from British Columbia south along both sides of the Cascades to northern California. It may be found eastward to Alberta, South Dakota, and Colorado.