According to Ceska and Ceska (2010), this species is "Native to North America, northern Europe and eastern Asia, widespread in North America (except Texas and SE states). Stem whitish, leaves with smaller number of "untidy" segments. Winter buds frequent, cylindrical."
Perennial aquatic from a short rhizome, stems 10-150 cm long, simple or forked, purplish, becoming white when dry.
In whorls of 3 or 4 mostly 1 cm or more apart, those of the middle whorls usually 3 cm long or more, simply pinnate with 11 or fewer segments; segments commonly more than 1.5 cm long, rather widely and irregularly spaced about 2-4 mm apart; winter buds well developed, 1-4 cm long, oval in outline, broadest in the middle.
Spikes almost naked, emergent, erect, to about 15 cm long; flowers in whorls, the lowermost female, the upper ones male, bright pink-red; the bract leaves shorter than flowers and fruits; petals oblong, concave, about 2.5 mm long; stamens 8.
Mericarps, 4, nearly round, 2-3 mm long, rounded on the back, glabrous or slightly wrinkled.
In Hitchcock et al. (1961) plants of these species would key out as "Myriophyllum spicatum var. spicatum."
If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.
Illustration Source: The Illustrated Flora of British Columbia
Synonyms and Alternate Names:
Myriophyllum exalbescens Fernald
Myriophyllum exalbescens var. magdalenense (Fern.) A. L÷ve
Myriophyllum magdalenense Fern.
Myriophyllum spicatum subsp. exalbescens (Fernald) HultΘn
Myriophyllum spicatum subsp. squamosum Laest. ex Hartm.
Myriophyllum spicatum var. capillaceum Lange
Myriophyllum spicatum var. exalbescens (Fernald) Jeps.
Myriophyllum spicatum var. squamosum (Laestad. ex Hartman) Hartman
There are ten species of Myriophyllum found in the Pacific Northwest (Ceska and Ceska 2010). View a key to the genus Myriophyllum for this region prepared by Oldriska Ceska and Adolf Ceska (BEN #428).