Potamogeton americanus

Potamogeton americanus Cham. & Schlecht
Linnaea 2 : 226. 1827.
Potamogeton fluilans Roth, Fl. Germ. 1 : 72, in part. 1788.
Potamogeton natans Thunb. Prodr. Fl. Cap. 32. 1794. Not P. nalans L. 1753.
Potamogeton nalans fluitans Torr. Fl. N. Y. 2 : 254. 1843.
Potamogeton lonchites Tuckerm. Am. Jour. Sci. II. 6 : 226. 1848.
Potamogeton plantagineus jamaicensis Griseb. Fl. Brit. W. Ind. 506. 1861.
Potamogeton lonchites noveboracensis Morong, Mem. Torrey Club 3 2 : 20. 1893.
Potamogeton americanus noveboracensis A. Benn. Jour. Bot. 31 : 297. 1893.
Potamogeio7i rectifolius A. Benn. Jour. Bot. 40 : 147. 1902.
Potamogeton pennsy Ivanicus portoricensis Graebner, Symb. Ant. 4 : 73. 1903.
Stems slender, much branched ; floating leaves petiolate ; blades coriaceous, elliptic, 2-12 cm. long, 0.5-3.5 cm. wide, 17-24-nerved, acute at the -apex and rounded or rarely acutish at the base ; petioles as thick as or a little thinner than the peduncles, 4-18 cm. long ; submerged leaves petiolate ; blades thin and pellucid, sometimes tinged with red, linearlanceolate, 10-30 cm. long, as wide or nearly as wide as the floating leaf-blades, 7-nerved, sometimes with intermediary secondary nerves ; t stipules 2-10 cm. long, acute, acuminate or obtuse ; spikes cylindric, 2-6 cm. long, many-flowered ; peduncles thickening upward, as long as or much longer than the spike ; nutlets smooth, 3-keeled, the middle keel prominent and sometimes slightly winged ; embryo a complete spiral, the curved apex pointing just inside the base.
Type locality : Carolina.
"Distribution : Vermont to Washington, south to Virginia, southern California, Texas, and
Mexico ; also in Cuba, Haiti, and Jamaica.