Potamogeton pusillus L.

Potamogeton pusillus I,. Sp. PL 127. 1753
Potamogeton pusillus vulgaris Fries, Novit. ed. 2. 48. 1828.
Potamogeton pusillus gemmiparus Robb. in A. Gray, Man. ed. 5. 489. 1867.
Potamogeton gemmiparus Morong, Bot. Gaz. 5 : 51. 1880. Potamogelon pusillus polyp hyllus Morong, Bot. Gaz. 5: 51. 1880.
Potamogeton pusillus panormitanus A. Benn. Jour. Bot. 19: 67. 1881. Potamogeton pusillus Sturrockii A. Benn. Jour. Bot. 21 : 279. 1883. Potamogeton pusillus elongatus A. Benn.; Macoun, Cat. Can. PI. 5: 371. 1890. Potamogeton pusillus capitatus A. Benn. Jour, Bot. 39 : 201. 1901. Potamogeton pusillus pseudo-rulilus A. Benn. Jour. Bot. 39: 201. 1901. Potamogelon strictifohus A. Benn. Jour. Bot. 40 : 148. 1902.
Stem slender, much branched, with propagating buds; leaves all submerged, linear or capillary, either slender and recurved or stiff and erect, 2-12 cm. long, 0.1-1.5 mm. wide, the apex obtuse, acute or mucronate, the base with 2 small glands ; primary nerves 1-3, often reticulated between, or the whole leaf apparently nerveless; stipules axillary and free from the leaf-bases, hyaline, 0.5-1.5 cm. long, the apex obtuse, or mucronate with the extreme tip aristate ; spikes cylindric and interrupted or capitate ; peduncles as thick as the stem or thinner, 1-5 cm. long, erect or recurved ; nutlets smooth or ultimately pitted, distinctly 3-keeled, or without keels and with 2 grooves on the back of the nutlet, the keels or edges of the grooves smooth ; style never exceeding 1 mm., straight or recurved; embryo a complete spiral, the curved apex pointing inside the base.
Type locality : Europe.
Distribution : Nova Scotia to British Columbia, south to Louisiana, southern California, and northern Mexico.