(Printer Friendly Version-pdf-121 KB) (Download a free copy of Adobe Acrobat Reader)

Stuckenia filiformis (Pers.) Boerner ssp. alpinus (Blytt) Hayer, Les & Kral

Photo: Northern Slender Pondweed

Northern Slender Pondweed

Habitat: Alkaline ponds and stream. [Open water (non-forested, wetland)]

Range: Greenland to Alaska, south to northern New England, New York, and west to Utah (ssp. alpinus).

Photo: Northern Slender Pondweed

Aids to Identification: Stuckenia filiformis ssp. alpinus is a pondweed with floating leaves absent and submersed leaves linear. Stipules are fused to leaf sheaths for at least 1 cm. Leaves are 0.2-0.8 mm wide, not lobed at base, tips blunt, obtuse, or notched (rarely apiculate). S. filiformis spp. alpinus is 10-30 cm long, with tightly clasping, persistent leaf sheaths.

Photo: Northern Slender Pondweed

Ecological characteristics: In Maine, this species is mostly restricted to a few marl ponds of Aroostook county. Marl ponds are themselves rare in Maine. Sites where these plants have been found range in pH from 7.3 to 9.1. The variety occidentalis is far rarer than the variety alpinus.

Phenology: A perennial; fruits (often helpful for identification) ripen in August - September.

Family: Potamogetonaceae

Synonyms: Formerly known as Potamogeton filiformis Pers. var. alpinus (Blytt) Aschers. & Graebn.; Coleogeton filiformis (Pers.) D. Les & R. Haynes ssp. alpinus (Blytt) D. Les & R. Haynes

Known Distribution in Maine: This rare plant has been documented from a total of 12 town(s) in the following county(ies): Aroostook.

Photo: Northern Slender Pondweed

Dates of documented observations are: 1940 (2), 1972 (2), 1973 (2), 1979 (4), 1998, 1999 (2), 2002

Reason(s) for rarity: Southern limit of range; suitable habitat naturally scarce.

Conservation considerations: Maintain hydrologic integrity of its alkaline water habitat.