Potamogeton perfoliatus

HABIT: Submersed aquatic arising from a white rhizome; flowering and fruiting July-October; seldom fruiting in the southern part of its range, including Ohio.

SIMILAR SPECIES: Non-fruiting specimens are easily confused with Potamogeton praelongus or P. richardsonii. These closely related species are difficult to identify unless mature fruit are present.

TOTAL RANGE: Nfld. to Ont., s. to NY, NC, PA, and OH; also along the Gulf Coast from FL to LA; the typical variety is circumboreal in North America and Eurasia.

STATE RANGE: COSHOCTON CO.: Ohio Canal near Roscoe, n.d. ca. 1835 , J.L. Riddell (CINC, GH, US). OTTAWA CO.: Put-in-bay, Aug. 1898, A.J. Pieters (US). See Comments below for a discussion of these specimens.

STATE STATUS: 1980 to present: Presumed Extirpated.

HABITAT: Calcareous to brackish waters of lakes and streams.

HAZARDS: Mechanical disturbance of substrate; alteration of drainage.

RECOVERY POTENTIAL: Unknown, but probably poor.

INVENTORY GUIDELINES: Collect mature fruiting specimens if possible; leave rhizome intact; while vegetative material is difficult to identify, this species fruits so rarely that the collector may have no alternative to gathering sterile material.

COMMENTS: Although is species is listed for Ohio by most manuals; all the Ohio specimens actually may be referred to Potamogeton richardsonii. Ogden (1943) cited the specimens listed above as P. perfoliatus. However, Ogden later changed his opinion. In a letter quoted in Braun (1967, p. 41) Ogden stated that all the Ohio material was intermediate between P. perfoliatus and P. richardsonii "but...closer to P. richardsonii." The specific boundaries between these species of pondweed and the related P. praelongus are very unclear. Many specimens appear to be hybrids or intergrades.

SELECTED REFERENCES:

Braun, E.L. 1967. The Monocotyledonae of Ohio : Cat-tails to orchids. The Ohio State Univ. Press, Columbus, OH. 464 p.

Hellquist, C.B. and G.E. Crow. 1980. Aquatic Vascular plants of New England: Part 1. Zosteraceae, Potamogetonaceae, Zannichelliaceae, Najadaceae. New Hampshire Agric. Exp. Sta., Durham, NH. 68 p.

Ogden, E.C. 1943. The broad-leaved species of Potamogeton of North America, north of Mexico. Rhodora 45: 57-105, 119-163, 171-214.

Ogden, E.C. 1974. Potamogeton in New York. New York St. Mus. Bull. No. 43. 20 p.

Ohio Department of Natural Resources

Division of Natural Areas and Preserves

Created: 3/1985 Allison W. Cusick

Database Code: SPGC.H55