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

Tussock (grass)

Tussock grasses or bunch grasses are found as native plants in natural ecosystems, as forage in pastures, and as ornamental grasses in gardens....

 native to various subantarctic

Subantarctic

The Subantarctic is a region in the southern hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° – 60° south of the Equator. The subantarctic region includes many islands in the southern parts of the Indian Ocean, Atlantic Ocean and...

 islands. The specific epithet honours British explorer James Cook

James Cook

Captain James Cook, FRS, RN was a British explorer, navigator and cartographer who ultimately rose to the rank of captain in the Royal Navy...

 who visited the Kerguelen Islands in 1776.

Description

Poa cookii is a deep green, perennial, gynomonoecious

Plant sexuality

Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....

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

Leaf

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

-sheaths forming a tangled mass at the base of the plant. It is a smaller plant than Poa foliosa

Poa foliosa

Poa foliosa is a species of tussock grass commonly known as Muttonbird Poa. It is native to the subantarctic islands of New Zealand and Australia.-Description:...

with which it may grow. The grass flowers from November to February.

Distribution and habitat

The grass is found on the Prince Edward

Prince Edward Islands

The Prince Edward Islands are two small islands in the sub-antarctic Indian Ocean that are part of South Africa. The islands, named Marion Island and Prince Edward Island, are located at ....

, Crozet

Crozet Islands

The Crozet Islands 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 Antarctic Lands.-Geography:...

, Heard

Heard Island and McDonald Islands

The Heard Island and McDonald Islands are an Australian external territory and volcanic group of barren Antarctic islands, about two-thirds of the way from Madagascar to Antarctica. The group's overall size is in area and it has of coastline...

 and Kerguelen Islands

Kerguelen Islands

The Kerguelen Islands , also known as the Desolation Islands, are a group of islands in the southern Indian Ocean constituting the emerged part of the otherwise submerged Kerguelen Plateau. The islands, along with Adélie Land, the Crozet Islands and the Amsterdam and Saint Paul Islands are part of...

 of the southern Indian Ocean

Indian Ocean

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

, as well as on Australia’s Macquarie Island

Macquarie Island

Macquarie Island lies in the southwest corner of the Pacific Ocean, about half-way between New Zealand and Antarctica, at 54°30S, 158°57E. Politically, it has formed part of the Australian state of Tasmania since 1900 and became a Tasmanian State Reserve in 1978. In 1997 it became a world heritage...

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

Peat

Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...

 flats with the cushion plant

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...

 Azorella selago

Azorella selago

Azorella selago is a species of cushion plant native to the sub-Antarctic islands of the Southern Ocean, including the Crozet Islands, the Possession Islands, the Heard Island and McDonald Islands, the Kerguelen Islands, and the Prince Edward Islands. The closely related Azorella macquariensis,...

. 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

Penguin

Penguins are a group of aquatic, flightless birds living almost exclusively in the southern hemisphere, especially in Antarctica. Highly adapted for life in the water, penguins have countershaded dark and white plumage, and their wings have become flippers...

 colonies where it has a competitive advantage over the dominant Poa foliosa. On Macquarie it has been severely affected by rabbit

Rabbit

Rabbits are small mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world...

 grazing

Grazing

Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...

.