Canon SX40 HS
Photographed in empty commercial lot Crestview HIlls, KY.
Musk or Nodding Thistle (Carduus nutans)
Musk Thistle Images © John M. Randall/The Nature Convervancy
DESCRIPTION: Several native thistles exist in prairies that may be confused with exotic species. Verify identification before initiating control work.
Musk thistle is a large, biennial herb. Leaves are dark green with a light-green midrib, smooth and hairless on both sides, coarsely lobed, slightly wavy, and arranged alternately on a stem that appears winged. Each lobe ends with a prominent spine. First year rosette leaves can be up to 24 inches long. Plant height varies from two to seven feet. The terminal flower of musk thistle is large—1 1/2 to 3 inches in diameter—solitary, and usually nodding or slightly bent over. The stem is freely branched.
Plumeless thistle is similar, but with many leaf-like spines on the stem, and hair on the underside of the leaf. In addition, the red to purple flowers of plumeless thistle are much smaller—usually about one third the size of musk thistle flowers. Plumeless thistle flowers are single or clustered, erect on the stems, and usually do not droop or nod. These two thistles can hybridize, and both are very similar in the rosette stage.
Bull thistle is also a biennial with prickly, winged stems. The leaves are coarse and spiny above with wooly white hairs below. A purple “brush” of flowers emerges from a spiny green ovoid base.
copied from here: http://dnr.wi.gov/invasives/fact/thistles_musk.htm
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