See text Acaena is a genus of about 60 species of mainly evergreen, creeping herbaceous perennial plants and subshrubs in the family Rosaceae, native mainly to the Southern Hemisphere, notably New Zealand, Australia and South America, but with a few species extending into the Northern Hemisphere, north to Hawaii (A. exigua) and California (A.

The word is written variously bidi-bidi, biddy-biddy, biddi-biddi, biddi-bid and a number of other variations.

The species Acaena microphylla has gained the Royal Horticultural Society's Award of Garden Merit.

[4] The generic name Acaena is derived from the Greek "akaina" (thorn), referring to the spiny hypanthium.

Acaena novae-zelandiae, one of the bidibids from New Zealand, is the most commonly encountered species in the United Kingdom, where it is often abundant on coastal sand dunes, crowding out native vegetation and creating an often painful nuisance with the barbed burrs.