Coefficient of Conservatism:
Coefficient of Wetness:
A. A. Reznicek
Rock outcrops in the Upper Peninsula from the limestones of Drummond Island to the granites and conglomerates farther west; also in dry open oak forests and sandy or grassy places (lawns, roadsides, dry prairies).
This perennial species is widespread in temperate regions of the world. Most of our plants are the native subsp. strictum, which is short (not more than ca. 20 cm) and clump-forming. Plants of roadsides, lawns, and other disturbed habitats mostly in southern Michigan may be the introduced Eurasian subsp. arvense, which is strongly rhizomatous, forming mats, and relatively tall (to at least 30 cm). The differences do not seem very clear in herbarium material, and stated differences in anther length and sepal length do not seem completely correlated with habitat and growth form.