Potamogeton perfoliatus subsp. richardsonii (Bennett) Hult.
FamilyPotamogetonaceae — APG family: Potamogetonaceae
SynonymsPotamogeton richardsonii (Bennett) Rydb., Potamogeton perfoliatus var. richardsonii Bennett
DescriptionAll leaves submerged; stem densely covered with ovate-lanceolate, dark-green, often undulate leaves clasping stem all around; stipules short, soon disintegrating into fibers; peduncles short, curved, not thicker toward apex; spike brown, 1-2 cm long.
EcologyLakes. P. perfoliatus described from Europe, subsp. Richardsonii from the Great Lakes.
Alaskan fruiting specimens have cavity in endosperm loop, a characteristic of subsp. Richardsonii. Leaves shorter in some specimens, as in subsp. perfoliatus of Furasia; longer in others, as in American plants. Hybrids with P. gramineus not uncommon. Broken line on circumpolar map indicates range of subsp. perfoliatus.
Hultén's Flora About

This is a digital representation of Eric Hultén’s ‘Flora of Alaska and Neighboring Territories: A Manual of the Vascular Plants’, which was published by Stanford University Press in 1968. The book was digitized by C. Webb (at UAMN) as part of the Flora of Alaska project, with funding by the US NSF (Grant 1759964 to Ickert-Bond & Webb), and with permission of Stanford University Press. Data and images © 1968 Board of Trustees of the Leland Stanford Jr. Univ. Usage licence: Creative Commons BY-NC-SA 4.0. NB: You may find OCR errors; please refer to the hard-copy if in doubt.