Stuckenia filiformis (Pers.) Börner
Common Name: NARROW-LEAVED PONDWEED
Synonym: Potamogeton filiformis, Potamogeton vaginatus
Coefficient of Conservatism: 7
Coefficient of Wetness: -5
Wetness Index: OBL
Physiognomy: Nt P-Forb

Stuckenia filiformis R.W. Smith

Potamogeton filiformis of Michigan Flora.

Lakes (including the Great Lakes) and rivers, at depths up to at least 1.2 m, but apparently fruiting best in shallow water over a sandy bottom. Represented in Michi­gan by two subspecies, which each occur ± throughout. The common subsp. filiformis is a compact plant typically 10–30 cm long with narrow leaves mostly not over 0.5 mm broad and stipular sheaths tightly clasping (< 2 mm wide) throughout; the uncommon subsp. occidentalis (J. W. Robbins) R. R. Haynes, Les, & M. Král is a larger plant ca. 20–100 cm long with leaves up to 1.2 (–2.5) mm wide and stipular sheaths loose, those at the base of the stem (2–) 2.5–5 mm wide (Potamogeton vaginatus of Michigan Flora). Some specimens treated as Potamogeton vaginatus in Michigan Flora are also the hybrid Stuckenia ×suecica (K. Richt.) Holub (S. filiformis × S. pectinata), which may be overlooked in our flora; see Kaplan (2008).

Locations

Alcona County
Alger County
Alpena County
Antrim County
Barry County
Bay County
Benzie County
Charlevoix County
    Including Beaver Island
Cheboygan County
Chippewa County
Crawford County
Dickinson County
Emmet County
Gogebic County
Grand Traverse County
Huron County
Iron County
Jackson County
Kalamazoo County
Kalkaska County
Kent County
Keweenaw County
    Only on Isle Royale
Lake County
Lapeer County
Leelanau County
    Including Manitou Islands
Livingston County
Luce County
Mackinac County
    Including Bois Blanc, Mackinac, Round Islands
Manistee County
Marquette County
Menominee County
Midland County
Missaukee County
Montcalm County
Montmorency County
Newaygo County
Oakland County
Otsego County
Presque Isle County
Roscommon County
Schoolcraft County
St. Clair County
Washtenaw County
Wayne County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 16, 2017. http://www.michiganflora.net/species.aspx?id=2346.