Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
55. Potamogetonaceae, the Pondweed Family
1. Potamogeton L. -- Pondweed
13. Potamogeton pectinatus L. -- Sago pondweed
Stems terete, ca. 1 mm thick, or the main stem stouter on deep water
forms, sparingly branched at the base, becoming freely dichotomously branched
above, 3-10 dm long. Leaves all submersed, filiform to narrowly linear,
3-12 cm long, usually 0.2-1 mm wide, 1- to 3-nerved, acute, sometimes wider
with obtuse tips early in the growing season or on plants from running water;
stipules adnate to the base of the leaf blade for 1-3 cm, forming a sheath
about as wide as the stem, occasionally wider on the main stem, especially in
deep water forms. Spikes elongate, 1-5 cm long, with 2-5(7) unevenly
spaced floral whorls; peduncles lax, filiform, to 15 cm long. Fruits
yellowish to tawny, drying brown, obliquely obovoid, 2.7-4 mm long, rounded
on the back, apiculate due to the style beak which is usually 0.3-0.5 mm long.
Jun--Sep. Shallow to rather deep, fresh to subsaline water of lakes, ponds,
marshes, ditches, rivers and streams; common and often abundant; (Nearly cosmopolitan).
Potamogeton pectinatus, upper portion with fruiting spike.
Previous Section -- Potamogeton nodosus Poir.
-- Longleaf pondweed
Return to Family -- Potamogetonaceae - The
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