Potamogeton foliosus Raf.

• Authority

  Haynes, Robert R. & Holm-Nielsen, Lauritz B. 2003. Potamogetonaceae. Fl. Neotrop. Monogr. 85: 1-52. (Published by NYBG Press)

• Family

  Potamogetonaceae

• Scientific Name

  Potamogeton foliosus Raf.

• Description

  Species Description - Rhizomes absent; erect stems slightly compressed, ridged, without spots, 4-75 cm long. Leaves submersed, sessile, ± spirally arranged, delicate, entire, noncrisped, pale green to olive, rarely rufescent, linear, nonarcuate, l-3(-5)-veined, 1.3-8.2 cm x 0.3-2.3 mm, apex noncucullate, acute to apiculate, rarely with a bristle, the base not clasping, without basal lobes, lacunae absent or to 2 rows each side of midrib; glands absent or rarely present, black to gold, to 0.5 mm diam.; ligules inconspicuous, free from blade, nonligulate, greenish to brown or rarely white, delicate to fibrous, rarely shredding at tip, persistent, 0.2-2.2 cm long. Turions uncommon, soft, lateral or terminal, 0.9-2.5 cm x 0.62.0 mm; inner leaves rolled into a hardened fusiform structure; outer leaves 1-3 per side, acute to apiculate, without corrugations at base. Inflorescences unbranched; peduncles similar, clavate, mostly in axils of lower, rarely upper leaves, usually recurved, 0.3-1.1 (-3.7) cm long; spikes all similar, capitate to cylindric, 1.5-7 mm long. Fruits sessile, obovate to near circular, turgid, pale green to olive or brown, with undulate, winglike abaxial keel, without lateral keels, 1.4-2.7 x 1.1-2.2 mm; beak erect, 0.2-0.6 mm long; sides without basal tubercles; embryo with ca. one full spiral.

• Discussion

  The species has been divided into two subspecies (Haynes & Hellquist, 1996), one subspecies is known from the Neotropics.