Canada Thistle :  n : European thistle naturalized in United States and Canada where it is a pernicious weed [syn: Canada thistle, creeping thistle, Cirsium arvense]

Thistle \This"tle\, n. [OE. thistil, AS. [thorn]istel; akin to D. & G. distel, OHG. distila, distil, Icel. [thorn]istill, Sw. tistel, Dan. tidsel; of uncertain origin.] (Bot.) Any one of several prickly composite plants, especially those of the genera Cnicus, Craduus, and Onopordon. The name is often also applied to other prickly plants. Blessed thistle, Carduus benedictus, so named because it was formerly considered an antidote to the bite of venomous creatures. Bull thistle, Cnicus lanceolatus, the common large thistle of neglected pastures. Canada thistle, Cnicus arvensis, a native of Europe, but introduced into the United States from Canada. Cotton thistle, Onopordon Acanthium. Fuller's thistle, the teasel. Globe thistle, Melon thistle, etc. See under Globe, Melon, etc. Pine thistle, Atractylis gummifera, a native of the Mediterranean region. A vicid gum resin flows from the involucre. Scotch thistle, either the cotton thistle, or the musk thistle, or the spear thistle; -- all used national emblems of Scotland. Sow thistle, Sonchus oleraceus. Spear thistle. Same as Bull thistle. Star thistle, a species of Centaurea. See Centaurea. Torch thistle, a candelabra-shaped plant of the genus Cereus. See Cereus. Yellow thistle, Cincus horridulus. Thistle bird (Zo["o]l.), the American goldfinch, or yellow-bird ({Spinus tristis); -- so called on account of its feeding on the seeds of thistles. See Illust. under Goldfinch. Thistle butterfly (Zo["o]l.), a handsomely colored American butterfly ({Vanessa cardui) whose larva feeds upon thistles; -- called also painted lady. Thistle cock (Zo["o]l.), the corn bunting ({Emberiza militaria). [Prov. Eng.] Thistle crown, a gold coin of England of the reign of James I., worth four shillings. Thistle finch (Zo["o]l.), the goldfinch; -- so called from its fondness for thistle seeds. [Prov. Eng.] Thistle funnel, a funnel having a bulging body and flaring mouth.