Phyllachne colensoi, the yellow cushionplant, is a species of 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...

 in the Stylidiaceae

Stylidiaceae

The family Stylidiaceae is a taxon of dicotyledonous flowering plants. It consists of five genera with over 240 species, most of which are endemic to Australia and New Zealand. Members of Stylidiaceae are typically grass-like herbs or small shrubs and can be perennials or annuals...

 family. It is native to both New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

 and Tasmania

Tasmania

Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...

, with colonisation of the latter being a somewhat recent dispersal. Phyllachne colensoi is frequently the dominant vegetation in upland bog habitats and is found throughout high mountain areas in New Zealand, but is only recorded from 12 sites in Tasmania in the west and south-west of the island.

Phyllachne colensoi is a perennial

Perennial plant

A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

 cushion mound-forming plant with short erect stems that are densely packed. Leaves are sessile and small at only 2-3 mm long. Solitary flowers are white and held close to the cushion mound, with flowers and fruits being produced from December to March.

Phyllachne colensoi was first described as Helophyllum colensoi by Joseph Dalton Hooker

Joseph Dalton Hooker

Sir Joseph Dalton Hooker OM, GCSI, CB, MD, FRS was one of the greatest British botanists and explorers of the 19th century. Hooker was a founder of geographical botany, and Charles Darwin's closest friend...

 in 1864 and then moved to the genus Phyllachne by Sven Berggren

Sven Berggren

Sven Berggren was a Swedish botanist, explorer and university professor. He was a professor at Lund University 1883-1902, later at Uppsala University. He was elected a member of the Royal Swedish Academy of Sciences in 1880....

in 1877.