Vascular Plants of North Carolina
Account for Slender Pondweed - Potamogeton berchtoldii   Fieber
Members of Potamogeton with account distribution info or public map:
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Section 5 » Family Potamogetonaceae
DistributionScattered in the northern and central Coastal Plain, as well as single sites in the eastern Piedmont and southern mountains. Thus, the overall range in the state is quite unclear. Note that this is only a small part of the P. berchtoldii as in RAB (1968), which showed numerous records over most of the Coastal Plain and inland, as well. Most of those records are now in P. pusillus.

This is a very widespread species, from across most of Canada and the US, absent only from a few states in the center of the US.
AbundanceRare to uncommon in the northern Coastal Plain, and very rare elsewhere in the state (at best). The website editors suggest a State Rank of S2? and placement on the Watch List.
HabitatThis is a species of still or slowly-moving waters, mainly in millponds and other lakes and ponds.
See also Habitat Account for General Herbaceous Ponds
PhenologyFlowers and fruits from May to September.
IdentificationThis species and P. pusillus are very similar and can be difficult to separate. Both have submerged leaves only (thus no floating leaves), and these are both alternate and opposite, linear, only about 1.5 inches long but barely 1/20-inch wide. The stem is quite branched in the upper portions. The leaves have only a single strong nerve, with single indistinct nerves on each side. There are stipules at the leaf bases, about 2/5-inch long, but they quickly fall off. However, at the base of each leaf is (usually) a nodal gland, which is lacking in the quite similar P. foliosus; you will need a hand lens to see this character. There are numerous spikes (to about 2/5-inch long) from upper leaf axils; in this species the inflorescence is continuous, whereas in P. pusillus the spike is interrupted. See Weakley (2018) for additional character differences.
Taxonomic CommentsWeakley (2018) indicates that nominate subspecies berchtoldii is the one present in NC.

Other Common Name(s)Small Pondweed, Berchtold's Pondweed. Small Pondweed is typically used for P. pusillus.
State Rank[S2?]
Global RankGNA [G5]
State Status[W7]
US Status
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