Coefficient of Conservatism:
Coefficient of Wetness:
B. S. Walters
Agropyron trachycaulum of Michigan Flora.
Widespread, but perhaps most often in dry or rocky forests and savannas (oak, jack pine, hickory), sand barrens, shores, and dunes; also recorded for fens and tamarack swamps; sometimes along roadsides and in other disturbed places.
All our plants are apparently referable to the highly variable subsp. trachycaulus (Barkworth, Campbell & Salomon 2007).
Fortunately, this extremely variable species can usually be easily recognized, if young by the short anthers, and if old by the very readily disintegrating spikelets (as also Pseudoroegneria spicata). In addition, the rachilla is nearly always strongly villous with fine, flexible hairs, especially in those forms most likely to be otherwise confused with other species (none of which have villous rachillas).
Occasionally some nodes of the spike may bear 3 spikelets, but such plants have only 1 spikelet at most nodes; they may also be distinguished from E. glaucus, which they resemble, by the villous rachilla, the generally narrower leaf blades, and the wider glumes.
Certain plants from the Huron Mountain area, Marquette Co., and elsewhere on the Lake Superior shore appear to be hybrids of E. trachycaulus and E. repens. The plants have the rhizomatous habit and long anthers (4–5 mm) of the latter species; the rachilla is glabrous or villous, disarticulating as in E. trachycaulus, and the glumes and lemmas are prominently awned.