New zealand-bur

Acaena novae-zelandiae, the bidgee-widgee, biddy-biddy, or red bidi-bidi, is a low mat-forming perennial herb in the family Rosaceae native to Australia (including Tasmania), New Zealand, New Guinea, and adjacent islands, and widely naturalized in temperate Europe, the British Isles, the Falklands, and parts of South America after introduction through the wool trade and as a garden escape. The plant produces wiry creeping stems that root at the nodes and form extensive low ground-covering mats only a few centimetres tall. Leaves are alternate, pinnate, 4-10 cm long, with 9-15 ovate to obovate leaflets that are sharply serrate, glaucous to dark green above and paler beneath, often tinged red or coppery in cold weather. The flowers are borne in compact terminal globose heads 1-1.5 cm across on slender erect peduncles 8-15 cm long, the individual flowers small, apetalous, with four greenish-white sepals and four protruding red-purple stamens that give the head a brushy purplish-red appearance at anthesis. After fertilization the fruit forms a dry achene enclosed in a globular bur 1.5 cm across, conspicuously armed with four (or more) stiff barbed reddish-pink spines that adhere strongly to fur, socks, and clothing — the principal means of long-distance dispersal.