Hill's Thistle (Cirsium hillii) (Canby 1891) |
Synonyms: Cirsium pumilum var. hillii, Cnicus hillii |
Hill's Thistle is a perennial forb restricted primarily to the Great Lakes Region of North America. In Canada, this species is confined to the shores of Lake Huron, including Manitoulin Island, and the the Bruce Peninsula. In the USA, it is found in Michigan, Wisconsin, Minnesota, Iowa, Illinois and Indiana. Hill's Thistle grows in a variety of open, dry habitats, including dry sandy grasslands, oak-pine barrens, dunes, and alvars. The most significant limiting factor for this species is habitat loss, either through forest encroachment, in the absence of fire, or through site development.
Cirsium hillii is generally recognized as a valid species, but has also been treated as a subspecies or variety of the Pasture Thistle (C. pumilum), widely distributed in the eastern United States. Flora of North America (2006) treats Cirsium hillii as Cirsium pumilum var. hillii.
D33107 Hill's Thistle (Cirsium hillii) Bruce Peninsula Ontario, Canada Copyright © Michael Patrikeev All Rights Reserved |
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