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. pinnatifida).[2]

Acaena
Acaena novae-zelandiae foliage and various fruiting stages
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Rosales
Family: Rosaceae
Subfamily: Rosoideae
Tribe: Sanguisorbeae
Subtribe: Sanguisorbinae
Genus: Acaena
Mutis ex L.[1]
Species

See text

Synonyms[1]
  • Ancistrum J.R.Forst. & G.Forst.

The leaves are alternate, 4–15 centimetres (1.6–5.9 in) long, and pinnate or nearly so, with 7–21 leaflets. The flowers are produced in a tight globose [inflorescence] 1–2 centimetres (0.39–0.79 in) in diameter, with no petals. The fruit is also a dense ball of many seeds; in many (but not all) species the seeds bear a barbed arrowhead point, the seedhead forming a burr which attaches itself to animal fur or feathers for dispersal.

Several Acaena species in New Zealand are known by the common name bidibid. The word is written variously bidi-bidi, biddy-biddy, biddi-biddi, biddi-bid and a number of other variations. These names are the English rendition of the original Māori name of piripiri.[3] The plant is also called the New Zealand burr. The species Acaena microphylla has gained the Royal Horticultural Society's Award of Garden Merit.[4]

Etymology

edit

The generic name Acaena is derived from the Greek "akaina" (thorn), referring to the spiny hypanthium.[5]

Species

edit

As of 2020, Plants of the World Online accepted the following species:[6]

Invasive species

edit

Some species have been introduced accidentally to other areas, attached to sheep's wool, and have become invasive species. 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. In California, A. pallida, A. novae-zelandiae and A. anserinifolia are considered serious weeds.[7]

References

edit
  1. ^ a b "genus Acaena". Germplasm Resources Information Network (GRIN) online database. Retrieved 30 March 2020.
  2. ^ RHS A-Z encyclopedia of garden plants. United Kingdom: Dorling Kindersley. 2008. p. 1136. ISBN 1405332964.
  3. ^ Orsman, H. W. (1999). The Dictionary of New Zealand English. Auckland: Oxford University Press.
  4. ^ RHS Plant Selector Acaena microphylla AGM / RHS Gardening
  5. ^ Bryony Macmillan. "Rosaceae 26. Acaena". E-Flora (Flora of North America). Retrieved 2015-12-03.
  6. ^ "Acaena". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 30 March 2020.
  7. ^ "Weeds Sorted by Pest Rating", CFDA.ca.gov
edit