''Lyallia kerguelensis'', commonly called the lyallia cushion (''coussin de lyallia'' in

French French may refer to: * Something of, from, or related to France ** French language, which originated in France ** French people, a nation and ethnic group ** French cuisine, cooking traditions and practices Arts and media * The French (band), ...

), is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

flowering Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

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 ...

in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Lyallia'' of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Montiaceae Montiaceae are a family of flowering plants, comprising about 14 genera with about 230 known species, ranging from small herbaceous plants to shrubs. The family has a cosmopolitan distribution. The family Montiaceae was newly adopted in the APG ...

. It is sometimes placed in the Hectorellaceae or the Portulacaceae. The generic name honours British

botanist Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

and naval officer

David Lyall David Lyall (1817–1895) MD, RN, FLS, was a Scottish botanist who explored Antarctica, New Zealand, the Arctic and North America and was a lifelong friend of Sir Joseph Hooker. He was born in Auchenblae, Kincardineshire, Scotland on 1 June 181 ...

who served as assistant surgeon on HMS ''Terror'' on the Antarctic exploring expedition led by

James Clark Ross Sir James Clark Ross (15 April 1800 – 3 April 1862) was a British Royal Navy officer and explorer of both the northern and southern polar regions. In the Arctic, he participated in two expeditions led by his uncle, Sir John Ross, John ...

from 1839 to 1843. Lyall was a friend and colleague of describer

Joseph Dalton Hooker Sir Joseph Dalton Hooker (30 June 1817 – 10 December 1911) was a British botanist and explorer in the 19th century. He was a founder of geographical botany and Charles Darwin's closest friend. For 20 years he served as director of the Ro ...

on the expedition when the type material was collected. 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 ...

refers to the type locality.

Description

''Lyallia kerguelensis'' is a

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 ...

herb Herbs are a widely distributed and widespread group of plants, excluding vegetables, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal purposes, or for fragrances. Culinary use typically distingu ...

. It forms round cushions, usually 200–400 mm across, but occasionally up to 1 m in diameter. Its closest relative is the similar cushion plant '' Hectorella caespitosa'' which is found in alpine areas of the

South Island The South Island ( , 'the waters of Pounamu, Greenstone') is the largest of the three major islands of New Zealand by surface area, the others being the smaller but more populous North Island and Stewart Island. It is bordered to the north by ...

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

.Wagstaff & Hennion (2007).

Distribution and habitat

The species is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the

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 ...

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 ...

, part of the

French Southern and Antarctic Lands The French Southern and Antarctic Lands (, TAAF) is an overseas territory ( or ) of France. It consists of: * Adélie Land (), the French claim on the continent of Antarctica. * Crozet Islands (), a group in the southern Indian Ocean, south ...

in 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), ...

. It grows in small populations on

moraine A moraine is any accumulation of unconsolidated debris (regolith and Rock (geology), rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a gla ...

s and

fellfield A fellfield or fell field comprises the environment of a slope, usually alpine or tundra, where the dynamics of frost (freeze and thaw cycles) and of wind give rise to characteristic plant forms in scree interstices. Soil dynamics The freeze-tha ...

s, from the sea shore to about 300 m above sea level, and can live for at least 16 years.

References

Notes

Sources

* * * Montiaceae Flora of the Kerguelen Islands Monotypic Caryophyllales genera Plants described in 1847 Cushion plants Taxa named by Joseph Dalton Hooker {{Caryophyllales-stub