Potamogeton nodosus Poir.

  • 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 nodosus Poir.

  • Type

    Type. Canary Islands. Broussonet s.n. (P-n.v.).

  • Synonyms

    Potamogeton mexicanus A.Benn., Potamogeton occidentalis Sieber ex Cham. & Schltdl., Potamogeton rotundatus Hagstr.

  • Description

    Species Description - Rhizomes present; erect stems terete, without spots, to 100 cm long. Leaves petiolate, both submersed and floating, or floating absent, ± spirally arranged; submersed leaves lax, entire, noncrisped, light to dark green, linear lanceolate to lance-elliptic, nonarcuate, 7-15-veined, 9-20 x 1-3.5 cm, with 2-5 rows of lacunae each side of midrib, the apex noncucullate, acute, the base acute, without basal lobes, the glands absent, the petiole 2-13 cm long, the basal sheaths conspicuous, free from blade, not ligulate, light brown, nonflbrous, not shredding at tip, 3-9 cm long; floating leaves with blades lenticular to elliptical, light green above, 9-21-veined, 3-11 x 1.5-4.5 cm, the apex acute to rounded, the base cuneate to rounded, the petiole 3.5-26 cm long. Turions absent. Peduncles cylindric, erect to ascending, 3-15 cm long; spikes cylindrical, 2-7 cm long. Fruits sessile, obovate, red to reddish-brown, with well-developed abaxial keel and muricate lateral keels, 2.7-4.3 x 2.5-3 mm; beak erect, ventral; sides plump, without basal tubercles; embryo with one full spiral.

  • Discussion

    Bennett (1887) listed two collections, Schmitz s.n. (BM) and Schaffner 199 (B), in the protologue of Potamogeton mexicanus. We have examined Schmitz s.n., which is in fruit. The Alismatidae specimens at B were destroyed during World War II, and, although we have examined specimens from many herbaria housing Schaffner specimens, we have not located a sheet of Schaffner 199. Consequently, the only original material that survives is the collection by Schmitz, a duplicate of which is at P. The sheet at BM matches the protologue and was examined by Bennett prior to drafting of the description. We have chosen to designate it the lectotype.

    Chamisso and Schlechtendal (1827) listed two collections in the protologue of Potamogeton occidentalis, Sieber 275 from Martinique and Poiteau s.n. from Dominique. We have examined both specimens, and both represent what we now know as Potamogeton nodosus. The authors credited the name to Sieber since it had been placed on an illustration without any description, which was based on Sieber’s collection from Martinique. We have chosen the Sieber collection as the lectotype since it maintains current usage, was examined by Chamisso and Schlechtendal, and was collected by the person to whom they credited the name.

    Hagström (1916) listed four collections when he named Potamogeton rotundatus: Pringle 1390 from Mexico, Edwards from California, U.S.A, Rydberg from Nebraska, U.S.A., and Fendler from New Mexico, U.S.A. We have examined all four collections and consider them all to represent the same taxon, what we presently consider to be P. nodosus. As pointed out by Ogden (1945), only the Pringle collection is in fruit, it being immature. We here designate Pringle 1390 as the lectotype since it is fertile, whereas the others are sterile or in flower.

  • Distribution

    North America; Mexico, West Indies, Central America, South America; Eurasia, and Africa. Common in clear to turbid waters of lakes, streams, rivers, and sloughs, from sea level to 2500 m.

    Mexico North America| Aguascalientes Mexico North America| Chiapas Mexico North America| Chihuahua Mexico North America| Colima Mexico North America| Distrito Federal Mexico North America| Durango Mexico North America| Hidalgo Mexico North America| Jalisco Mexico North America| México Mexico North America| Oaxaca Mexico North America| Puebla Mexico North America| San Luis Potosí Mexico North America| Tamaulipas Mexico North America| Veracruz Mexico North America| Guatemala Central America| Izabal Guatemala Central America| Cuba South America| Cienfuegos Cuba South America| La Habana Cuba South America| Holguín Cuba South America| Matanzas Cuba South America| Santiago de Cuba Cuba South America| Piñar del Río Cuba South America| Jamaica South America| Cornwall Jamaica South America| Saint Elizabeth Jamaica South America| Saint James Jamaica South America| Jamaica South America| Saint Ann Jamaica South America| Saint Catherine Jamaica South America| Jamaica South America| Saint Andrew Jamaica South America| Haiti South America| Dominican Republic South America| Puerto Rico South America| Antigua and Barbuda South America| Guadeloupe South America| Dominica South America| Martinique South America| Venezuela South America| Distrito Federal Venezuela South America| Zulia Venezuela South America| Trinidad and Tobago South America| Brazil South America| Bahia Brazil South America| Pará Brazil South America|