Contains 10 accepted taxa overall.
Characteristics
Classification
Citation
POTAMOGETON Linnaeus, Sp. Pl. 126. 1753.
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TYPE: Potamogeton natans Linnaeus Lectotypified by Taylor, in Britton, N. Amer. Fl. 17(1): 14, 30. 1909.
Species
| Scientific Name | Common Name | Herbarium Specimens | Status | Photos |
|---|---|---|---|---|
| Potamogeton berchtoldii ssp. berchtoldii | Small Pondweed | |||
| Potamogeton confervoides | Alga Pondweed, Conferva Pondweed, Tuckerman's Pondweed | |||
| Potamogeton diversifolius | Common Snailseed Pondweed | |||
| Potamogeton epihydrus | Ribbonleaf Pondweed | |||
| Potamogeton foliosus var. foliosus | Leafy Pondweed | |||
| Potamogeton illinoensis | Illinois Pondweed | |||
| Potamogeton nodosus | Longleaf Pondweed, American Pondweed | |||
| Potamogeton oakesianus | Oakes’s Pondweed | |||
| Potamogeton pulcher | Spotted Pondweed, Heartleaf Pondweed | |||
| Potamogeton pusillus | Small Pondweed |
Identification Key
1. Stipular sheaths of submersed leaves adnate to base of leaf blade, tip projecting as ligule
1. Stipular sheaths of submersed leaves free from base of leaf blade or with only 1/–5 sheath adnate, ligule not obvious
2
2. Submersed leaf blade filiform, linear, or ribbon-like, 0.1-10 mm wide
3
2. Submersed leaf blades broadly linear-oblong, lanceolate, elliptic, to nearly orbiculate, 3-58 mm wide (occasional stranded plants without submersed leaves)
6
3. Rhizomes present; floating leaves present, at least in some plants in population
4
3. Rhizomes absent; floating leaves absent
5
4. Lacunae prominent in submersed leaves
4. Lacunae absent in submersed leaves
5. Fruits with abaxial keel or ridge
5. Fruits with abaxial surface rounded
6
6. Leaf blade with 0-2 rows of lacunae along midrib, apex acute, rarely apiculate, rarely with bristle; stipules connate; peduncles filiform to cylindric, 1-3 per plant; inflorescences interrupted; mature fruits obovoid, sides concave, beak toward adaxial edge, rarely median
6. leaf blade with 1-5 rows of lacunae along midrib, apex acute to obtuse; stipules convolute; peduncles cylindric, more than 3 per plant; inflorescences continuous; mature fruits widest at middle or ovoid, sides rounded, beak median, not toward adaxial edge
7. Stem flattened; leaf blade margins conspicuously serrate; fruit beak 2–3 mm; turions formed, hard
7. Stem terete; leaf blade margins entire; fruit beak 1 mm or less; turions rarely formed
8
8. Submersed leaves clasping stem; floating leaves absent
8. Submersed leaves petiolate or sessile (not clasping); floating leaves present
9
9. Stem conspicuously rusty- or black-spotted; floating leaf blade rounded to cordate at base; submersed leaf blades crispate, mostly arcuate
9. Stems without spots; floating leaf blade cuneate, tapering to petiole, rounded; submersed leaf blades flat or crispate, mostly not arcuate or occasionally arcuate
10
10. Submersed leaves sessile or petioles to 4 cm long; larger submersed leaves acuminate at apex; fruits grayish green to olive-green
10. Submersed leaves with petioles 0.5-13 cm long; larger submersed leaves acute at apex but without sharp awl-like tip; fruits red to reddish brown
Genus Synonyms
| Synonym | Full Citation | Basionym | Type |
|---|---|---|---|
| No synonyms found. | |||