Aquatic and Wetland Vascular Plants of the Northern Great Plains
55. Potamogetonaceae, the Pondweed Family
1. Potamogeton L. -- Pondweed1. Potamogeton alpinus Balbis
Stems terete, 1-2 mm thick, simple or rarely branched above, to 1 m long; foliage reddish-tinged, especially the upper leaves and peduncles. Submersed leaves linear-lanceolate to linear-oblong, 4-18 cm long, 5-15(20) mm wide, usually 7(-11)-nerved, blunt and obtuse to rarely acutish at the tip, narrowed to a sessile base. Floating leaves often lacking, thin and delicate, obovate or oblanceolate to elliptic-oblanceolate, mostly 4-6 cm long, 1-2 cm wide, 7- to 15-nerved, obtuse, tapering indistinctly into a short petiole. Stipules free, membranous, 1-2.5(4) cm long; spikes cylindric, with 5-9 crowded whorls of flowers, peduncles about as thick as the stem, 3-15 cm long. Fruits tawny-olive, obliquely obovoid, 2.5-3.5 mm long; dorsal keel usually narrow and prominent; lateral keels absent or low and rounded; beak short, curved backward. Jul--Sep. Cold streams and lakes in the Black Hills; (Circumboreal, in N.Amer. from Newf. to AK, s to MA, NY, WI, MN, SD, CO, UT and CA).
Reports of P. alpinus for outside of the Black Hills in this region
were based on misidentifications.
Return to Family -- Potamogetonaceae - The Pondweed Family
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