Vascular Plants of North Carolina
Account for Leafy Pondweed - Potamogeton foliosus   Rafinesque
Members of Potamogeton with account distribution info or public map:
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Section 5 » Order Najadales » Family Potamogetonaceae
AuthorRafinesque
DistributionScattered in the Coastal Plain, mostly in the lower/Eastern portions; also widely scattered in the mountains, but just a single Piedmont record (Granville County). The gap in the Piedmont is likely real.

This is a very widespread species across the continent, found across Canada and in all 50 US states. However, it is scarce south of the VA mountains, northern AR, and OK.
AbundanceRare in the Coastal Plain and mountains, and very rare to absent in the Piedmont. This is a Watch List species.
HabitatThis is a species of primarily calcareous waters underlain by limestone and marl, in NC. It occurs in still to slow-moving waters of lakes, ponds, and streams, including ones that are oligohaline or brackish near the coast.
See also Habitat Account for General Herbaceous Ponds
PhenologyFlowers and fruits from May to October.
IdentificationThis is a very slender species that is frequently branched, reaching 2-3 feet long, with all leaves being submerged. The leaves are linear, opposite or alternate, about 2 inches long but only 1/10-inch wide at most; there are 3-5 nerves on a leaf. In this species, there are no glands at the base of a leaf; you will need a hand lens to check this, but both P. berchtoldii and P. pusillus do have a gland at the base of each leaf. This species has very short spikes, conical but barely 1/8-inch long and wide, on fairly short stalks. The spikes of the other two species are cylindrical and about 2/5-inch long, and on moderately long stalks. Take great care when separating these three species, as only P. pusillus is numerous in the state.
Taxonomic CommentsThe taxon found in the state is the nominate variety -- var. foliosus.

Other Common Name(s)None. Note that this plant is hardly "leafy", at least no more so than most other pondweeds.
State RankS2
Global RankG5
State StatusW1
US Status
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