{{Short description|Species of flowering plant in the family Xyridaceae}} {{Speciesbox | image = Xyris marginata .jpg | image_caption = | genus = Xyris | species = marginata | authority = Rendle<ref name=apni>{{APNI2|id=|name=''Xyris marginata''}}</ref><ref name=rendle>{{cite journal|vauthors=Rendle AB|date=1899|title=Notes on Xyris|journal=Journal of Botany, British and Foreign|volume=37|page=503}}</ref> }}
'''''Xyris marginata''''', commonly known as the '''alpine yellow eye''', is a species of monocot flowering plant in the family Xyridaceae. It is endemic to Tasmania and King Island in Australia, where it commonly grows in button grass moorlands at altitudes of up to {{cvt|1070|m}} above sea level.<ref name="UTAS_Species">{{cite web |url=https://www.utas.edu.au/docs/plant_science/field_botany/species/monocots/xyridsp/xyrimarg.html |title=''Xyris marginata'' |website=Key to Tasmanian Vascular Plants |publisher=University of Tasmania |access-date=2026-02-24}}</ref> The species was first collected by German-Australian botanist Ferdinand von Mueller in 1875, and was formally described by Alfred Barton Rendle in 1899.<ref name="POWO">{{cite web |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:871564-1 |title=''Xyris marginata'' Rendle |website=Plants of the World Online |publisher=Royal Botanic Gardens, Kew |access-date=2026-02-24}}</ref>
== Taxonomy == The genus name ''Xyris'' is derived from the Latin word for iris, referencing the bright yellow flowers prominent in many species of the genus. The specific epithet ''marginata'' refers to the tightly rolled margins of the plant's leaves.<ref name="UTAS_Species"/>
There are four native species of ''Xyris'' in Tasmania: ''X. marginata'', ''X. muelleri'', ''X. operculata'', and ''X. tasmanica''.<ref name="UTAS_Key">{{cite web |url=https://www.utas.edu.au/dicotkey/dicotkey/aquat_mono/gXyris.htm |title=Key to Xyridaceae species in Tasmania |publisher=University of Tasmania |access-date=2026-02-24}}</ref> They all occupy waterlogged soils and swamps, with ''X. marginata'' thriving at the highest altitudes. ''X. operculata'' is the only species in this group that is not endemic to Tasmania.<ref name="UTAS_Key"/>
== Description == ''Xyris marginata'' is a tufted, perennial herb that forms small tussocks on high-altitude moors. Its most notable characteristics are its golden yellow flowers, twisting stems, and the wavy margins found on the bracts of its inflorescence. The main stalk, which ascends spirally from the roots, is between {{cvt|15|to|55|cm}} long. The leaf blades are {{cvt|1|mm}} broad and thick, featuring a central rib, and are characteristically dark brown and shiny. The leaf margins are rounded except at the awl-shaped tip, and the base sheathing is {{cvt|4|to|6|cm}} long.<ref name="UTAS_Species"/>
Like all Tasmanian species of ''Xyris'', ''X. marginata'' flowers between November and January. The flower head is broader towards the top, forming an almost spherical shape. It typically contains three sepals, three petals, and three stamens. The petals are rounded with finely notched margins—a defining trait of the species. The stamens possess anthers that protrude on short filaments, accompanied by hairy staminodes reaching towards the base. The flower also contains a three-lobed capsule that is hardened at the top. The surrounding bracts are dark brown, becoming larger and broader as they ascend the stem; their outlines are curved, irregularly torn, and darker towards the centre.<ref name="UTAS_Species"/>
=== Similar species === Altitude is a significant factor in identifying the species in the field, as other Tasmanian ''Xyris'' species generally lack the resilience to survive at high altitudes.<ref name="UTAS_Key"/> ''X. operculata'' can be differentiated from ''X. marginata'' by its slender, erect leaves, distinguishing it from the spring-like, spiralled leaves of ''X. marginata''. Additionally, ''X. operculata'' features three stamens reduced to hairy tufts alongside its three regular stamens. ''X. muelleri'' has leaves that curl upwards and are pointed at the ends, with petals that have consistent, smooth margins. ''X. tasmanica'' shares the consistent margins of ''X. muelleri'' but lacks leaves close to the flower head.<ref name="UTAS_Key"/>
== Distribution and habitat == ''Xyris marginata'' is primarily found in wet heaths and button grass moorlands across King Island, as well as the north-west, west, east, and south-west coasts of Tasmania.<ref name="UTAS_Species"/>
Button grass moorlands occupy approximately 14% of the state of Tasmania. This habitat includes alpine areas in the western and south-western regions, highlands in the north-east, and lowland heath pockets in the eastern and south-eastern parts of the island. The Tasmanian Department of Natural Resources and Environment defines these moorlands as vegetation typically less than {{cvt|2|m}} in height, dominated by the hummock-forming button grass (''Gymnoschoenus sphaerocephalus'').<ref name="DPIPWE_Moorland">{{cite web |url=https://nre.tas.gov.au/Documents/VCA-MBS.pdf |title=MBS Buttongrass moorland with emergent shrubs |publisher=Department of Natural Resources and Environment Tasmania |access-date=2026-02-24}}</ref> This encompasses various sub-types, including sparse moorlands on slopes, pure button grass moorlands, and moorlands with emergent shrubs.<ref name="DPIPWE_Moorland"/>
== Ecology == The button grass (''Gymnoschoenus sphaerocephalus'') is the defining ecological feature of the marshes where ''Xyris marginata'' thrives.<ref name="DPIPWE_Moorland"/> The depth of the peat substrate in these moorlands varies greatly; it can erode to a thickness of just {{cvt|1|cm}} over mineral soils or, more commonly, quartz gravels. These moorlands develop on flats, slopes, ridges, and mountain plateaus that are highly vulnerable to frequent fires. The soils are characteristically infertile and drain poorly, yet they support a high level of biodiversity, with approximately 272 vascular plant species recorded in this habitat, a third of which are endemic to Tasmania.
== Conservation == While there are no specific, independent conservation objectives exclusively for ''Xyris marginata'', its primary habitat—the button grass moors—is actively managed and protected by the Tasmanian Government. The majority of this moorland is publicly owned, resistant to invasive weeds, and maintained through controlled burning regimes when required.<ref name="DPIPWE_Moorland"/>
== References == {{reflist}}
== External links == * {{Wikispecies-inline|Xyris marginata}}
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Category:Xyris Category:Endemic flora of Tasmania Category:Plants described in 1899 Category:Taxa named by Alfred Barton Rendle