Shortspike Watermilfoil

Plants monoecious. Stem loosely erect in water, often whitish, few branched above, base characteristically curved or U-shaped on young plants; internodes distinct, ca. 1 cm. Submerged leaves 4- or 5-whorled, pectinate, ovate to oblong in outline; segments in 5-12 pairs, filiform, 1-5 cm. Inflorescence a terminal spike of 2-4-whorled flowers, mostly 4-10 cm; bracts shorter than or rarely equaling fruits. Male flowers: bracteoles oblong-spatulate or ovate-oblong, margin entire; petals pinkish; stamens 8. Female flowers: bracteoles mostly serrate or somewhat pectinate-toothed at margin; perianth absent or sepals vestigial. Fruit 4-loculed, globose, ca. 2 mm; mericarps abaxially tuberculate or aculeate. Fl. and fr. Apr-Sep.

Heilongjiang, Jiangsu, Jilin, Nei Mongol, Qinghai, Sichuan, Xinjiang, Xizang, Yunnan [Russia; North America].

Myriophyllum exalbescens Fernald; M. spicatum Linnaeus subsp. exalbescens (Fernald) Hultén; M. spicatum var. exal bescens (Fernald) Jepson; M. spicatum var. muricatum Maximowicz.

Myriophyllum sibiricum is a species of water milfoil known by the common names shortspike watermilfoil, northern watermilfoil, and Siberian water-milfoil. It is native to Russia, China, and much of North America, where it grows in aquatic habitat such as ponds and streams. It generally grows over a meter long, its green stem drying white. It is lined with whorls of fanlike green leaves divided into many narrow, feathery lobes.