8. Myriophyllum ussuriense (Regel) Maximowicz, Bull. Acad. Imp. Sci. Saint-Pétersbourg. 19: 182. 1873.
乌苏里狐尾藻 wu su li hu wei zao
Myriophyllum verticillatum Linnaeus var. ussuriense Regel, Mém. Acad. Imp. Sci. Saint Pétersbourg, Sér. 7, 4(4) [Tent. Fl.-Ussur.]: 60. 1861.
Plants dioecious, rarely monoecious or with bisexual flowers. Stem weak, 5-20 cm. Submerged leaves 3- or 4-whorled, pectinate, broadly lanceolate in outline, 5-10 × 2.5-5 cm; segments filiform, short, margin entire; emergent leaves 1 or 2, linear or lanceolate, minute, margin serrate to entire. Inflorescence of axillary flowers on emergent part of stem or a terminal spike; bracts and bracteoles elliptic, smaller than flowers, margin entire or serrate. Flowers 4-merous. Calyx tubular, shortly lobed. Petals pale reddish, obovate-oblong, ca. 2 mm. Stamens 8. Styles 4; stigmas white, long fimbriate. Fruit olive-brown, 4-loculed, subglobose, ca. 0.75 × 0.6 mm; mericarps finely tuberculate. Fl. May-Jun, fr. Jun-Aug.
Muddy waterside shallows; near sea level to 1800 m. Anhui, Guangdong, Guangxi, Hebei, Heilongjiang, Hubei, Jiangsu, Jilin, Jiangxi, Taiwan, Yunnan, Zhejiang [Japan, Korea, Russia].
In FRPS (53(2): 135. 2000), this species was included in Myriophyllum propinquum A. Cunningham, which is separated on the size and shape of the bracteoles and flowers and is restricted to Australia and New Zealand.