Vascular Plants of North Carolina
Account for Southern Waternymph - Najas guadalupensis   (Sprengel) Magnus
Members of Hydrocharitaceae:
Members of Najas with account distribution info or public map:
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Section 5 » Order Najadales » Family Hydrocharitaceae
Author(Sprengel) Magnus
DistributionPresent over the lower half of the Coastal Plain, and widely scattered elsewhere in the state, but with just a single Mountain collection. For some odd reason, though there are numerous Piedmont collections, there seem to be none in the western half of the Coastal Plain, a presumed artifact of collection of such an aquatic species.

This is a very widespread species, from southern Canada throughout the US, in all states. Thus, the near absence of montane county records is somewhat odd.
AbundanceFairly common in the lower Coastal Plain, and infrequent in the Piedmont. Rare (or absent?) in the western Coastal Plain and the mountains.
HabitatThis submerged species grows only in still or sluggish waters -- pools, ponds, lakes, and slow-moving rivers and creeks. This species often grows in brackish water, unlike with N. gracillima.
PhenologyFlowers and fruits from August to October.
IdentificationThis submerged species has a branched stem, with "stringy" branches reaching up to 1.5 inches long -- producing a tangled mat of vegetation. The opposite leaves are linear, about 2/3-inch long but barely 1/10-inch wide. This species has the widened leaf bases gradually tapered, whereas N. gracillima has a wide leaf base that is truncate or squared-off. Though D. guadalupensis has 20 or more teeth on a leaf margin, these are microscopic and practically invisible.
Taxonomic CommentsWeakley (2018) indicates that the nominate variety -- var. guadalupensis is the one present in NC.

Other Common Name(s)Southern Naiad, Common Waternymph, Guppy Grass
State RankS3 [S3S4]
Global RankG5
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