{{Short description|Flowering plant genus in the montia family}} {{Speciesbox | image = Lyallia kerguelensis.JPG | image_alt = | image_caption = Lyallia Cushion | genus = Lyallia | parent_authority = Hook.f. | species = kerguelensis | authority = Hook.f. }}
'''''Lyallia kerguelensis''''' is a species of flowering cushion plant in the monotypic genus '''''Lyallia''''' of the family Montiaceae.
==Description== ''Lyallia kerguelensis'' is a perennial that forms round cushions, usually 20–40 centimeters across, but occasionally up to 1 meter in diameter.{{sfn|Wagstaff|Hennion|2007|p=419}} Individual cushions have a mean diameter of 12.79 cm and mean height of 6.06 cm.{{sfn|Hennion et al. 2013|p=1588}} The plants have an extensive root system with a large main root and many fine branching roots.{{sfn|Marchand et al. 2021|p=19}} Plants can live for at least 16 years.{{sfn|Wagstaff|Hennion|2007|p=419}}
The flowers are tiny and mostly green.{{sfn|Farino|1991|p=52}} They are found are at the ends of the stems in the leaf {{plantgloss|axil|axils}}, where the leaves attach to the stems, usually in clusters of two to four.{{sfn|Wagstaff|Hennion|2007|pp=419–420}} Each flower has two somewhat green membrane-like sepals that fuse at the base. The four petals have a similar texture. Each flower has three stamens, but about one third of fully opened flowers only have two functional anthers.{{sfn|Wagstaff|Hennion|2007|p=420}}
Each translucent red-brown capsule has one or two kidney shaped black seeds.{{sfn|Wagstaff|Hennion|2007|p=420}} Unlike most plants endemic to the islands in the south Indian Ocean, its seeds are not highly viable.{{sfn|Hennion et al. 2013|p=1590}}
==Taxonomy== Both the genus ''Lyallia'' and the species ''Lyallia kerguelensis'' were scientifically described and named by Joseph Dalton Hooker with priority dated to 1847.{{sfn|POWO 2025b}}{{sfn|POWO 2025c}}{{sfn|Hooker|1860|p=548}} ''Lyallia'' is classified in the family Montiaceae, although it was formerly placed in the Portulacaceae and before that in Hectorellaceae.{{sfn|Farino|1991|p=52}}
''Lyallia kerguelensis'' is the only accepted species in the genus,{{sfn|POWO 2025b}} however one species was previously placed in it.{{sfn|POWO 2025d}} ''Reicheella andicola'' was initially described as ''Lyallia andicola'' by Rodolfo Amando Philippi in 1891 but was reclassified in 1900.{{sfn|POWO 2025d}} Additionally, it was proposed by B.L. Nyananyo and Vernon Heywood that ''Hectorella caespitosa'' be moved to the genus as ''Lyallia caespitosa'' in 1987.{{sfn|POWO 2025a}} It is a similar cushion plant from alpine areas that is endemic of the South Island of New Zealand.{{sfn|Wagstaff|Hennion|2007|p=417}} Genetic research has confirmed that ''H. caespitosa'' is the closest relative to ''Lyallia'',{{sfn|Wagstaff|Hennion|2007|p=421}} but the move to ''Lyallia'' has not been widely accepted in the field of botany.{{sfn|POWO 2025a}}
===Name=== The generic name honors British botanist and naval officer David Lyall who collected specimens of the plant.{{sfn|Lindsay|2005|p=231}} Lyall served as assistant surgeon on HMS ''Terror'' on the Antarctic exploring expedition led by James Clark Ross from 1839 to 1843.{{sfn|Lindsay|2005|pp=223, 226, 231}} Hooker also served as an assistant surgeon on the expedition, but aboard HMS Erebus.{{sfn|Lindsay|2005|p=227}}
==Range and habitat== The species is endemic to the Kerguelen Islands in the subantarctic, part of the French Southern and Antarctic Lands in the southern Indian Ocean.{{sfn|Wagstaff|Hennion|2007|p=419}} It grows in small populations on moraines and fellfields, from the sea shore to about 300 meters above sea level,{{sfn|Wagstaff|Hennion|2007|p=419}} at a mean elevation of 132.22 m.{{sfn|Hennion et al. 2013|p=1588}} It is present, but rare on the main island of the group, but is more common on Long Island in the Gulf of Morbihan.{{sfn|Young|Schofield|1973|p=243}}
Both ''Lyallia kerguelensis'' and ''Pringlea antiscorbutica'' were definitely present on the Kerguelen Islands during the late glaciation of the early Holocene some 10,000 years ago.{{sfn|Young|Schofield|1973|pp=245–246}} It is also probable that they are survivors from the richer group of plants that grew on the islands prior to the extensive glacial cover of the Pleistocene, prior to about 2.58 million years ago.{{sfn|Young|Schofield|1973|p=241}}
==References== {{Reflist}}
===Sources=== ;Books {{refbegin}} * {{Cite book |last1=Farino |first1=Teresa |date=1991 |title=The Photographic Encyclopedia of Wildflowers |url=https://archive.org/details/photographicency0000fari |url-access=registration |language=en |location=New York |publisher=Smithmark Publishers |isbn=978-0-8317-2806-9 |oclc=25998865 |access-date=29 June 2025}} * {{Cite book |last1=Hooker |first1=Joseph Dalton |author-link1=Joseph Dalton Hooker |date=1860 |title=The Botany of the Antarctic Voyage of H.M. Discovery Ships Erebus and Terror in the Years 1839–1843 :Under the Command of Captain Sir James Clark Ross |url=https://www.biodiversitylibrary.org/page/3011900 |language=en |location=London |publisher=Reeve Brothers |oclc=1041609057 |access-date=29 June 2025}} * {{Cite book |last1=Lindsay |first1=Ann |date=2005 |title=Seeds of Blood and Beauty : Scottish Plant Explorers |url=https://archive.org/details/seedsofbloodbeau0000lind |url-access=registration |language=en |volume= |edition= |location=Edinburgh, Scotland |publisher=Birlinn |isbn=978-1-84158-345-7 |oclc=60965620 |access-date=29 June 2025}} {{Refend}}
;Journals {{refbegin}} * {{cite journal |author1=Hennion, Françoise |author2=Martin-Tanguy, Josette |name-list-style=amp |year=1999 |title= Amine distribution and content in several parts of the subantarctic endemic species ''Lyallia kerguelensis'' (Hectorellaceae) |journal=Phytochemistry |volume=52 |issue=2 |pages= 247–251 |doi= 10.1016/S0031-9422(99)00191-0 |bibcode=1999PChem..52..247H }} * {{Cite journal |last1=Hermant |first1=Marie |last2=Prinzing |first2=Andreas |last3=Vernon |first3=Philippe |last4=Convey |first4=Peter |last5=Hennion |first5=Françoise |date=August 2013 |title=Endemic species have highly integrated phenotypes, environmental distributions and phenotype—environment relationships |url=https://www.researchgate.net/publication/264551567 |journal=Journal of Biogeography |language=en |volume=40 |issue=8 |pages=1583–1594 |doi=10.1111/jbi.12095 |issn=0305-0270 |jstor=23463677 |bibcode=2013JBiog..40.1583H |access-date=1 July 2025 |ref={{sfnref|Hennion et al. 2013}}}} * {{Cite journal |last1=Marchand |first1=Lorène Julia |last2=Tarayre |first2=Michèle |last3=Dorey |first3=Thomas |last4=Rantier |first4=Yann |last5=Hennion |first5=Françoise |date=January 2021 |title=Morphological variability of cushion plant ''Lyallia kerguelensis'' (Caryophyllales) in relation to environmental conditions and geography in the Kerguelen Islands: implications for cushion necrosis and climate change |journal=Polar Biology |language=en |volume=44 |issue=1 |pages=17–30 |doi=10.1007/s00300-020-02768-2 |bibcode=2021PoBio..44...17M |url=https://hal.science/hal-03036374 |ref={{sfnref|Marchand et al. 2021}}}} * {{Cite journal |last1=Wagstaff |first1=Steven J. |last2=Hennion |first2=Françoise |date=December 2007 |title=Evolution and biogeography of ''Lyallia'' and ''Hectorella'' (Portulacaceae), geographically isolated sisters from the Southern Hemisphere |url=https://www.researchgate.net/publication/231932917 |journal=Antarctic Science |language=en |volume=19 |issue=4 |pages=417–426 |doi=10.1017/S0954102007000648 |bibcode=2007AntSc..19..417W |s2cid=86781394 |access-date=29 June 2025}} * {{Cite journal |last1=Young |first1=Steven B. |last2=Schofield |first2=Eileen K. |date=1973 |title=Palynological Evidence for the Late Glacial Occurrence of ''Pringlea'' and ''Lyallia'' on Kerguelen Islands |url=https://www.biodiversitylibrary.org/part/122769 |journal=Rhodora |language=en |volume=75 |issue=802 |pages=239–247 |issn=0035-4902 |jstor=23311833 |url-status=live |archive-url=https://archive.org/details/biostor-138763 |archive-date=29 February 2020 |access-date=1 July 2025}} {{Refend}}
;Web sources {{refbegin}} * {{Cite POWO |last1=POWO |date=2025 |id=698874-1 |title=''Hectorella caespitosa'' Hook.f. |access-date=29 June 2025 |ref={{sfnref|POWO 2025a}}}} * {{Cite POWO |last1=POWO |date=2025 |id=6343-1 |title=''Lyallia'' Hook.f. |access-date=29 June 2025 |ref={{sfnref|POWO 2025b}}}} * {{Cite POWO |last1=POWO |date=2025 |id=155006-1 |title=''Lyallia kerguelensis'' Hook.f. |access-date=29 June 2025 |ref={{sfnref|POWO 2025c}}}} * {{Cite POWO |last1=POWO |date=2025 |id=218433-2 |title=''Reicheella andicola'' (Phil.) Pax |access-date=29 June 2025 |ref={{sfnref|POWO 2025d}}}} {{Refend}}
{{Taxonbar|from=Q16868040|from2=Q3019947}}
Category:Montiaceae Category:Flora of the Kerguelen Islands Category:Monotypic Caryophyllales genera Category:Plants described in 1847 Category:Cushion plants Category:Taxa named by Joseph Dalton Hooker