''Poa cookii'', sometimes called Cook's tussock-grass or bluegrass, is a species of

tussock grass Tussock grasses or bunch grasses are a group of grass species in the family Poaceae. They usually grow as singular plants in clumps, tufts, hummocks, or bunches, rather than forming a sod or lawn, in meadows, grasslands, and prairies. As perennia ...

native to various

subantarctic The sub-Antarctic zone is a physiographic region in the Southern Hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46th parallel south, 46° and 60th parallel south, 60° south of t ...

islands. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

honours British explorer

James Cook Captain (Royal Navy), Captain James Cook (7 November 1728 – 14 February 1779) was a British Royal Navy officer, explorer, and cartographer famous for his three voyages of exploration to the Pacific and Southern Oceans, conducted between 176 ...

who visited 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 subantarctic, sub-Antarctic region. They are among the Extremes on Earth#Remoteness, most i ...

in 1776.

Description

''Poa cookii '' is a deep green,

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

gynomonoecious Gynomonoecy is defined as the presence of both female and hermaphrodite flowers on the same individual of a plant species. It is prevalent in Asteraceae but is poorly understood. It is a monomorphic sexual system comparable with monoecy, andromon ...

grass growing as densely clumped tussocks up to 800 mm in height, with the fibres from older

leaf A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leav ...

-sheaths forming a tangled mass at the base of the plant. It is a smaller plant than '' Poa foliosa'' with which it may grow. The grass flowers from November to February.

Distribution and habitat

The grass is found on the Prince Edward, Crozet, Heard and

of the southern

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

, as well as on Australia's

Macquarie Island Macquarie Island is a subantarctic island in the south-western Pacific Ocean, about halfway between New Zealand and Antarctica. It has been governed as a part of Tasmania, Australia, since 1880. It became a Protected areas of Tasmania, Tasmania ...

. On Heard it occupies moist and sandy areas along the shore and on

peat Peat is an accumulation of partially Decomposition, decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, Moorland, moors, or muskegs. ''Sphagnum'' moss, also called peat moss, is one of the most ...

flats with the

cushion plant A cushion plant is a compact, low-growing, mat-forming plant that is found in alpine, subalpine, arctic, or subarctic environments around the world. The term "cushion" is usually applied to woody plants that grow as spreading mats, are limited i ...

'' Azorella selago''. On Macquarie it grows on rocky areas along the coast up to 200 m above sea level, on flats and slopes on wet peat and along the edges of creeks, often flourishing in the nutrient-rich soil near

penguin Penguins are a group of aquatic flightless birds from the family Spheniscidae () of the order Sphenisciformes (). They live almost exclusively in the Southern Hemisphere. Only one species, the Galápagos penguin, is equatorial, with a sm ...

colonies A colony is a territory subject to a form of foreign rule, which rules the territory and its indigenous peoples separated from the foreign rulers, the colonizer, and their '' metropole'' (or "mother country"). This separated rule was often or ...

where it has a competitive advantage over the dominant ''Poa foliosa''. On the Prince Edward Islands ''Poa cookii'' is eaten by caterpillars of the native moth '' Embryonopsis halticella.'' On Macquarie it has been severely affected by

rabbit Rabbits are small mammals in the family Leporidae (which also includes the hares), which is in the order Lagomorpha (which also includes pikas). They are familiar throughout the world as a small herbivore, a prey animal, a domesticated ...

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to free range (roam around) and consume wild vegetations in order to feed conversion ratio, convert the otherwise indigestible (by human diges ...

References

{{Taxonbar, from=Q13942989 cookii Flora of the Kerguelen Islands Flora of Macquarie Island Flora of the Prince Edward Islands Flora of Heard Island and McDonald Islands Flora of the Crozet Islands Plants described in 1879