Large, coarse plant. Leaves large, upper egg-shaped,
lower somewhat heart-shaped and wavy-edged. Flowers white
to pink to purple, in small prickly heads, somewhat resembling
thistle heads. Heads on very short stalks, or stalkless.
Fruit a prickly, clinging bur. Blooms in summer to fall.
A weed from Eurasia, common in waste places. In
Wildwood, occasional along bikeway, especially in South Meadow area
beyond the second bridge.
Combination of traits fairly distinctive. Flowers
resemble thistle heads, but thistles have prickly leaves.
Leaves may resemble some of the bitter dock (Rumex
obtusifolius), but flowers are completely different. Spotted
knapweed (Centaurea maculosa) and Tyrol knapweed (C. nigrescens) have somewhat similar
flowerheads, but they are more spreading and showy. Both species also have narrower leaves, and in spotted knapweed the leaves are divided into narrow lobes.
Great burdock (Arctium lappa) is similar, but larger
throughout, and with flower heads on long stalks; it has not
been reported from Virginia.