Rorippa curvipes var alpina
The Rocky Mountain states, plus small areas of Arizona, Nevada and Washington
Streambanks, lakeshores, moist meadows; 4,600 to 12,500 feet
Oblanceolate to oblong, up to 1.3 inches long, with irregularly lobed, toothed or wavy edges
June to September
Rorippa alpina is a low growing species found in moist locations, most commonly at the edges of lakes and streams; stems stay close to the ground, branching freely from the base and further up. All plant parts are hairless. Leaves are quite thick, growing at the base and along the stems at alternate intervals. Basal leaves (often withered by flowering) are usually pinnately lobed, and stalked, while stem leaves have toothed or wavy edges, and are sessile. Stems and sometimes sepals may be purplish.
The small, greenish yellow flowers form as compact clusters, becoming more elongated at the fruiting stage. The four sepals are oblong while the four petals are spatulate, and similar in length - less than 0.1 inches. Fruits are short green pods, wider towards the base, held on pedicels about a quarter of an inch long, angled upwards.