Common names: pond weed

Family: Potamogetonaceae

Could be confused with: Aponogeton, Callitriche, Echinodorus, Heteranthera, Hydrocleys, Najas.

Native distribution: Cosmopolitan.

Species commonly cultivated:
Potamogeton crispus L. (Cosmopolitan)
P. gayii A. Benn. (South America)
P. illinoensis Morong (North and South America)
P. octandrus Poir. (Asia, Australia)
P. schweinfurthii A. Benn. (Africa)
P. wrightii Morong (Asia)

Adventive distribution: Potamogeton crispus is introduced into North America and New Zealand.

Weed status: Numerous species of Potamogeton have been recorded as troublesome; P. nodosus, P. crispus, and Stuckenia pectinata (L.) Boerner (formerly Potamogeton pectinatus) are huge problems in irrigation systems in the western United States and several other countries.

Habit: Submersed, floating stem plant.

Brief description: Perennial or annual. Stem rhizomatous or stoloniferous, bearing specialized tubers (turions); vertical stems produced at nodes along horizontal stem. Leaves alternate or rarely opposite; submerged leaves thin, linear to lanceolate, margin entire, sometimes undulate; floating leaves (when present) thick, leathery, ovate, elliptic, oblong. Inflorescence an emergent spike. Flowers small, bisexual; perianth of 4 tepals. Dispersal by rhizome, stem fragments and seed.

Natural habitat: Still or slow-flowing waters of lakes rivers and streams.

Additional comments: A diverse genus in which many species form dense monoclonal stands.