Acaena novae-zelandiae, commonly known as red bidibid,[1] bidgee-widgee,[2] buzzy[3] and piri-piri bur,[4] is a small herbaceous, prostrate perennial, native to New Zealand, Australia and New Guinea,[5] of the family Rosaceae.

[6] Each flower produces one achene, bearing four approximately 10 mm long spines,[2] tipped with barbs,[2][5][7] which aid dispersal by attaching to wool, feathers and various clothing materials.

Acaena novae-zelandiae was first formally described in 1871 by Thomas Kirk who published the description in Transactions and Proceedings of the New Zealand Institute.

[2][7] It grows in freely draining soils such as silty and sandy loams, typically on sites which receive a high amount of sunlight.

This plant can be prevented from spreading by limiting disturbance to stolons, thus reducing vegetative propagation,[6] and by mowing flowers before the burrs form.