POTAMOGETONACEAE

By: Ganga D. Bhatt, Keshab R. Rajbhandari & Norbert Holstein

Taxon Description 

Perennial or annual aquatic herbs, occasionally semi terrestrial with creeping rhizomes present or absent. Stems elongated or shortened, terete to compressed. Leaves submerged or floating, sessile or petioled, alternate, rarely opposite, subopposite or whorled. Stipules free from leaves or adnate to leaf bases. Flowers whorled, in cylindric spikes on axillary peduncles, bisexual or unisexual. Tepals 4, free or absent, claw-shaped; stamens 4; carpels 1-9. Fruit drupaceous.

Taxon Statistics

Six genera and ca. 110 species, cosmopolitan; three genera and 11 species in Nepal.

Key to Genera

1 a. Flowers unisexual …………………………………..…………………………………………………………………………………………………………………………………….. 3. Zannichellia

b. Flowers bisexual ………………………………..………………………………………………………………………………………………………………………………………………………………… 2

2 a. Submerged leaves with stipules free from leaf base, leaf blades translucent, not channeled, flattened; peduncle compact …….….1. Potamogeton

b. Submerged leaves with stipules adnate to leaf blade, leaf blades opaque, channeled; peduncle lax  …………………………………….……………. 2. Stuckenia