Carduus spp.
Nuzzo (2001) notes that C. arvense can be confused with the closely related musk thistles (Carduus spp.). Distinguishing characteristics of C. arvense are small flowerheads (<2.5 cm high), dioecious plants, and stems that are not conspicuously spiny-winged. All species of Cirsium sp ("plumed thistle") have a pappus with branched hairs, in contrast to the unbranched pappus hairs on Carduus spp. ("plumeless thistle"). Cirsium vulgare black thistle (English), bull thistle (English), chardon (French), cirse commun (French), Scotch thistle (English), spear thistle (English)
Nuzzo (2001) notes that C. arvense can be confused with other thistles, especially bull thistle (C. vulgare). Distinguishing characteristics of C. arvense are small flowerheads (<2.5 cm high), dioecious plants, and stems that are not conspicuously spiny-winged. |