Russian Water-Milfoil

Description

Myriophyllum ussuriense is an aquatic or semi-aquatic plant from arhizome, with stems that are up to 10 in. (25 cm) tall. The leaves that rise out of the water are in whorls of 3 or opposite, 1/16 to 1/3 in. (1-8 mm) long, linear or lanceolate in outline and entire or pinnate with 1-3 pairs of segments. The submersed leaves are in whorls of 3 and pinnate, and broadly egg-shaped in outline, with 2-7 alternate segments on each side. The winter buds are 1/8 to - in. (3-7 mm) long, threadlike, and formed in the leaf axils. Male andfemale flowers develop on separate plants in the axils of the floral bracts. The floral bracts are similar to the leaves, and usually entire, or with a few stubby segments on each side. The white petals of the male flowers fall off in age and are about 1/8 in. (3mm) long, with 8 stamens that fall off in age. The female flowers are inconspicuous and greenish, with 4 feather-like stigmas.