Potamogeton pusillus L.
small pondweed
Potamogetonaceae (Horned pondweed family)
Introduction to Vascular Plants
small pondweed
Potamogetonaceae (Horned pondweed family)
Introduction to Vascular Plants
SUBTAXA PRESENT IN BC
Species Information
General:
Perennial, aquatic herb from fine, tufted roots; stems up to 100 cm long, sparingly branched.
Leaves:
All submersed, linear, the sides parallel, thin, green, 1-15 cm long, 0.3-3 cm wide, unstalked, usually with 3 veins, the tips pointed, the stipules 0.5-1 cm long, delicate, not fibrous, greenish or brownish, the margins fused, the veins obscure and faint, the basal glands at nodes well-developed.
Flowers:
Inflorescence spikelike, the spikes 0.5-1.5 cm long, with 2 to 5 whorls of flowers, the stalks thin; bases of the winter buds soft, smooth.
Fruits:
Achenes, almost rounded, 1.5-2.8 mm long, 1.6-2 mm wide, widest above the middle, the beaks short, stubby, the keels absent.
Notes:
Two subspecies, occasionally treated as separate species (e.g., Douglas et al 1994) can be distinguished in our area.
1. Stipules with fused margins; leaves without translucent bands along the midveins or with the bands up to 2-rows wide on each side of the midveins; marginal veins join the midveins about 2 mm from the leaf tips in a sharp angle....................ssp. pusillus
1. Stipules with overlapping margins; leaves with translucent bands up to 5-rows wide on each side of the midveins; marginal veins join the midveins about 0.5-1 mm from the leaf tips in a blunt (60 degree) angle....................ssp. tenuissimus (Mert. & Koch) Haynes & C.B. Hellquist
Habitat and Range
Lakes, ponds, sloughs and ditches in the lowland, steppe and montane zones; frequent in BC; circumpolar, N to AK, YT and NT, E to NF and S to ME, MA, PA, NC, FL, MS, LA, TX, NM, AZ and CA; Eurasia, Mexico, Africa.Status Information
Synonyms
Synonyms and Alternate Names:
Potamogeton berchtoldii Fieber
Potamogeton berchtoldii var. acuminatus Fieber
Potamogeton berchtoldii var. colpophilus (Fernald) Fernald
Potamogeton berchtoldii var. lacunatus (Hagstr.) Fernald
Potamogeton berchtoldii var. mucronatus Fieber
Potamogeton berchtoldii var. polyphyllus (Morong) Fernald
Potamogeton berchtoldii var. tenuissimus (Mert. & W.D.J. Koch) Fernald
Potamogeton gemmiparus (J.W. Robbins) J.W. Robbins ex Morong
Potamogeton pusillus subsp. groenlandicus (Hagstr.) Bocher
Potamogeton pusillus var. gemmiparus J.W. Robbins
Potamogeton pusillus var. mucronatus (Fieber) Graebn.
Potamogeton pusillus var. tenuissimus Mert. & W.D.J. Koch