About Trifolium parryi A.Gray
Trifolium parryi A.Gray is a short, herbaceous clover species that produces either very short stems or no stems at all, reaching a total height of 4 to 25 centimeters. Despite its small stature, it is the tallest clover species that grows in alpine tundra, and it bears larger, showier flowers than other alpine clovers. This species grows into continuous spreading mats via thin, branching rhizomes. Its leaves and stems grow from a structure called a caudex, and mature plants develop a prominent taproot. The leaves are compound, bearing the characteristic three leaflets of the Trifolium (clover) genus. Leaves attach directly to the base of the plant through small leaf stems called petioles, which range in length from 8 millimeters to 19 centimeters. Each of the three leaflets is 5–43 millimeters long and 1.5–16 millimeters wide, is hairless, has toothed edges near its base, and may be widest at its base, midpoint, or tip. Flower heads rise above the leaf canopy on flower stems called peduncles, which measure 1.8–22 centimeters long and grow from existing stems when stems are present. Each rounded flower head holds 5 to 30 very small individual flowers. Individual flowers are 12–22 millimeters long, colored deep pink to rose, and are distinctly fragrant. In its native habitat, flowering occurs from June to September, during summer and early fall. The fruit is a simple carpel commonly called a pod, which holds 1 to 4 seeds. As the pods develop and ripen, the flower petals wither, turn yellow-brown, and remain enclosing the pods. Trifolium parryi is native to the Rocky Mountains in the Western United States. In Montana, it occurs in Madison, Gallatin, Park, and Carbon Counties, all counties surrounding Yellowstone National Park. In Idaho, it has only been recorded in Fremont County, which borders Gallatin County, Montana. In Wyoming, it grows in two northern counties (Park and Hot Springs) and two southern counties (Carbon and Albany). It is found across many eastern counties of Utah, and in most mountainous counties of Colorado. In New Mexico, it only grows in Taos County. In alpine tundra, Trifolium parryi is adapted to grow in areas covered by snowbanks, even though this snow cover limits its growing season to fewer than 80 days. In the subalpine zone, it grows in meadows and along streams and creeks. Across all of its habitats, it prefers rocky soils, and will grow on rocky scree slopes formed by landslides and at the bases of cliffs. It grows at elevations between 3350 and 4025 meters. NatureServe evaluated Trifolium parryi as globally secure (G5) in 2001. Within its range, it has been ranked as apparently secure (S4) in Montana and vulnerable (S3) in Wyoming, and has not been evaluated in the rest of its distribution. Ecologically, Trifolium parryi relies on the golden-belted bumblebee for pollination. Plants produce more seed in areas with higher populations of this bumblebee species.
