''Acaena magellanica'', commonly called buzzy burr or greater burnet, is a species of flowering plant whose range includes the southern tip of South America and many subantarctic islands.

Description

''Acaena magellanica'' is a perennial, mat-forming plant with creeping stems, up to high. The leaves are oblong to linear-lanceolate, with 5 to 10 pairs of ovate leaflets. The flower heads are globular and grow on wiry stems well clear of the foliage. They are followed by brown, prickly seed heads; the seeds have small hooks which enables them to adhere to clothing, feathers or fur.

Distribution and habitat

The species is native to the southern part of South America. Its range includes Argentina, Chile and various sub-Antarctic islands including the Falkland Islands, the

Kerguelen Islands The Kerguelen Islands ( or ; in French commonly ' but officially ', ), also known as the Desolation Islands (' in French), are a group of islands in the sub-Antarctic constituting one of the two exposed parts of the Kerguelen Plateau, a large ...

, the Prince Edward Islands,

Crozet Islands The Crozet Islands (french: Îles Crozet; or, officially, ''Archipel Crozet'') are a sub-Antarctic archipelago of small islands in the southern Indian Ocean. They form one of the five administrative districts of the French Southern and Antarcti ...

, South Georgia and the South Sandwich Islands and the Heard Island and McDonald Islands. Its typical habitat is damp places such as the edge of bogs, the banks of streams, waterlogged places, meadows and forest margins. It grows from sea level to an altitude of about .

Ecology

In South Georgia, ''Acaena magellanica'' may cover the ground in dense patches. It is deciduous, and when the leaves are shed, mosses like ''

Tortula robusta ''Tortula'' is a genus of mosses in the family Pottiaceae. Species There are different classifications for the species included in the genus. The delimitation of genus Tortula is problematic and was subject to a number of alterations in the pa ...

'', which grows underneath, flourish. The

are in the Southern Indian Ocean Islands tundra ecoregion which is characterised by tussock grasses, lichens and liverworts. ''A. magellanica'' is one of the few low forbs that grew here, but the introduction of the European rabbit (''Oryctolagus cuniculus''), which selectively grazes the species it prefers, eliminated many of the native forbs. When the rabbit was eradicated, ''A. magellanica'' and other forbs failed to recover because years of herbivory had depleted their seed banks, and introduced species such as annual meadow grass (''Poa annua''),

mouse-ear chickweed ''Cerastium'' is a genus of annual, winter annual, or perennial plants belonging to the family Caryophyllaceae. They are commonly called mouse-ear chickweed. Species are found nearly worldwide but the greatest concentration is in the northern ...

(''Cerastium fontanum'') and dandelion (''Taraxacum officinale'') out-competed them.

References

magellanica Flora of southern Chile Flora of South Argentina Flora of the subantarctic islands Île Amsterdam Plants described in 1791 {{Rosoideae-stub