Eriocapitella rivularis, a species of flowering plant in the buttercup family Ranunculaceae, is native to Asia. The specific epithet rivularis means "waterside, of the rivers", which evidently refers to one of its preferred habitats. It is commonly called the riverside windflower. In Chinese, it is called cao yu mei, which means "grass jade plum".
Eriocapitella rivularis is a perennial herbaceous plant with a rhizome-like root structure. It is a clump-forming plant with 3 - 5 basal leaves, each with a petiole long, occasionally up to long. The leaf blades are lobed with three sections. Each leaf, being wider than it is long, has the overall shape of a pentagon. In addition to the basal leaves, there are 1 - 3 flowering stems, each long, occasionally up to long. A whorl of 3 or 4 leaves (technically bracts) wraps around each stem. The stem leaves are similar in appearance to the basal leaves but somewhat smaller. Multiple (3 - 5) pubescent flower stalks rise directly from the stem leaves, each stalk being long. The single flower at the end of each stalk has 5 - 10 sepals, but no petals. Each sepal is long and wide. The petal-like sepals are usually white, tinged with blue on the reverse. There are 30 - 60 pistils in the center of the flower, surrounded by stamens long, tipped with steel-blue anthers. The fruits are beaked achenes long, ovoid in shape with hooked styles.
In its native habitat, E. rivularis flowers from May to August. Each flower is approximately in diameter.
Eriocapitella rivularis was described by Maarten J. M. Christenhusz and James W. Byng in 2018. Like other members of genus Eriocapitella, E. rivularis was formerly a member of genus Anemone. The basionym Anemone rivularis Buch.-Ham. ex DC. was described in 1817.
Eriocapitella rivularis is native to Asia. It is found throughout the Himalaya region, across much of South Asia, East Asia, and Southeast Asia, ranging as far south as Sumatra in western Indonesia.
Its preferred habitats include meadows, forest margins, paddy fields, streamsides, and lakesides. It is also found under alpine brush in the Himalayas at elevations up to 4900m (16,100feet).