Bidens beckii Spreng.
Common Name: WATER-MARIGOLD
Synonym: Megalodonta beckii
Coefficient of Conservatism: 10
Coefficient of Wetness: -5
Wetness Index: OBL
Physiognomy: Nt P-Forb

Megalodonta beckii of Michigan Flora.

Lakes, ponds, rivers, and streams. While the deepest recorded depth in Michigan is 4.6 m, this species flowers (and fruits) best in relatively quiet and shallow water.

Though often recognized as the monotypic genus Megalodonta, the molecular phylogeny of Ganders, Berbee, & Pirseyedi (2000) strongly suggest that it belongs in Bidens. Though the heads are like other species of Bidens with ray flowers, the submersed foliage is often superficially confused with that of other dissected-leaved aquatics. The submersed leaves (opposite but branching at the base so appearing whorled) differ from those of Myriophyllum and Rorippa aquatica in lacking a central axis and in being much branched; from those of Ranunculus, Utricularia, and Rorippa aquatica in being opposite (or seemingly whorled), without bladders. The bushy appearance of the leaves surrounding the stem at the nodes, with bare internodes between, gives vegetative pieces, which are often seen washed up on shores, a distinctive tiered aspect (shared only with Utricularia purpurea). The simple, opposite, toothed emersed leaves are very different.

Locations

Alcona County
Alger County
Benzie County
Berrien County
Branch County
Cass County
Charlevoix County
    Only on Beaver Island
Cheboygan County
Chippewa County
    Including Drummond Island
Clare County
Emmet County
Gogebic County
Houghton County
Ingham County
Iosco County
Iron County
Jackson County
Kalamazoo County
Kent County
Keweenaw County
    Including Isle Royale
Leelanau County
Lenawee County
Livingston County
Luce County
Mackinac County
Manistee County
Marquette County
Mason County
Mecosta County
Missaukee County
Muskegon County
Newaygo County
Oakland County
Ogemaw County
Ontonagon County
Oscoda County
Otsego County
Presque Isle County
Roscommon County
Schoolcraft County
St. Clair County
Van Buren County
Washtenaw County
Wexford 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=407.