Isoetes echinospora Durieu
Common Name: SPINY QUILLWORT
Coefficient of Conservatism: 9
Coefficient of Wetness: -5
Wetness Index: OBL
Physiognomy: Nt Fern Al

Isoetes echinospora D. F. Brunton

Our commonest quillwort, widespread in shallow water (from almost emergent to more than one meter depth) in ponds, lakes and slow-moving rivers with nutrient poor, acidic, sandy or gravelly bottoms.

The North American subspecies of this cosmopolitan species is ssp. muricata (Durieu) Á. Löve & D. Löve. The leaves of this diploid (2n = 22) species are narrow, flexible, and bright green to yellow green. The megaspores are small (up to 0.55 mm in diameter); the ornamentation makes them appear spiky (like a miniature medieval mace) under high power in a dissecting microscope or through a 10× hand lens.

The rare hybrid Isoetes ×hickeyi W. C. Taylor & N. T. Luebke (I. echinospora × I. lacustris) has been collected in Alger and Gogebic Cos.

Locations

Alger County
Baraga County
Barry County
Cass County
Charlevoix County
    Only on Beaver Island
Cheboygan County
Chippewa County
Delta County
Dickinson County
Gogebic County
Houghton County
Iron County
Kalamazoo County
Kent County
Keweenaw County
    Including Isle Royale
Luce County
Mackinac County
Marquette County
Ontonagon County
Osceola County
Otsego County
Presque Isle County
Schoolcraft County
St. Clair County
Wayne County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 12, 2017. http://michiganflora.net/species.aspx?id=1488.