Northern Snail-seed Pondweed (Potamogeton spirillus)

Old Mill Brook Bottom

The Northern Snail-seed Pondweed (Potamogeton spirillus), also called the Spiral-fruited Pondweed or Spiral Pondweed, is a perennial forb/herb in the Pondweed Family (Potamogetonaceae) and order, Najadales. The family and genus names are from the Greek for "neighbor of a river."  The species name means spiraled. The order name is from the Greek and Latin verb "to swim." As a noun, the order name refers to a water nymph. The following photographs are details from the photograph above that was taken in a pool of the Old Mill Creek. Unfortunately, the pool had a higher water level than usual submerging the floating leaves. This plant prefers shallow and placid waters. The turbidity of French Hill Pond and their small size makes these plants difficult to photograph.

Northern Snail-seed Pondweed (Potamogeton bicupulatus)

The fully submersed leaves of this plant are linear, up to three inches (eight centimeters) long, narrow and arranged alternately along stems in a spiral fashion. The spiral nature of these leaves is difficult to see in the photographs because the leaves are so small and the water rather turbid. The floating leaves are elliptical and up to 1½ inches (3.5 centimeters) long. The stipules (sheaths covering the base of leaves) are fused to the leaves for half the length of the floating leaves. 

Northern Snail-seed Pondweed (Potamogeton bicupulatus)

The flowers are very small and difficult to see. They are green-brown, cylindrical clusters. The seeds are dry and disk-like, resembling snail shells whence the common name.

The root system is rhizomic.

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