Coefficient of Conservatism:
Coefficient of Wetness:
Calamagrostis lacustris, Calamagrostis inexpansa
Including C. inexpansa and C. lacustris of Michigan Flora.
Fens, sedge meadows, interdunal swales, low dunes, and moist cobbly, sandy, or rocky shores, especially of the Great Lakes, often in calcareous habitats; sometimes in drier rocky sites.
Several collections from wet places in Kalamazoo Co., and one (O. A. Farwell 12563½ in 1940, BLH) said to have come from conglomerate shores of Lake Superior east of Eagle Harbor, Keweenaw Co., are subsp. stricta, with upper ligules 1.5–2.5 (–3) mm long; leaf blades mostly smooth below and involute; palea less than 2 mm long; and longer callus hairs ca. 1.7–2.2 mm long.
Subspecies inexpansa (C. inexpansa of Michigan Flora) is widespread throughout the state, though uncommon southward, and has the upper ligules mostly 3.5–7.5 (–8) mm long; leaf blades ± antrorsely scabrous below, involute to flat; palea (1.8–) 2–3.2 mm long; and longer callus hairs ca. 2.4–3.2 (–3.4) mm long. As in subsp. stricta, the awn is straight or at most very obscurely twisted, usually inserted about the middle of the lemma, the palea is mostly about 0.5 mm (or more) shorter than the lemma, and callus with hairs immediately below the middle of the lemma shorter than those of the lateral tufts.
A few collections from rock crevices and rocky openings on igneous rocks, mostly on or near the shores of Lake Superior (specimens from Houghton, Iron, and Marquette Cos. plus Isle Royale (Keweenaw Co.) can be contrasted with typical C. stricta subsp. inexpansa by having the awn twisted at base, mostly bent at middle (the tip therefore protruding from the sides of some of the spikelets), inserted on lower third of lemma; palea nearly or quite as long as lemma; and callus lacking hairs immediately below the middle of the lemma. These were called C. lacustris in Michigan Flora, but are now subsumed into a broad concept of C. stricta subsp. inexpansa as a regional race.
Only subspecies stricta and the "lacustris" race are listed as threatened.