''Caladenia longicauda'' subsp. ''eminens'', commonly known as the stark white spider orchid, is a plant in the orchid family Orchidaceae and is endemic to the

south-west The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A compass rose is primarily composed of four cardinal directions—north, east, south, and west—each se ...

of Western Australia. It has a single hairy leaf and up to three large, bright white flowers with long, broad, spreading lateral sepals and

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s, a relatively broad labellum with short, narrow teeth. It is a relatively common orchid found in a broad band, mainly between Tenterden and Jerramungup. Caladenia longicauda subsp

Description

''Caladenia longicauda'' subsp. ''eminens'' is a terrestrial, perennial, deciduous,

herb In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...

with an underground tuber and a single hairy leaf, long and wide. Up to three, bright white flowers long and wide are borne on a spike tall. The dorsal sepal is erect, the lateral sepals are long and wide and the petals are wide. The labellum is white, more than wide and the

column A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. ...

is a less than long. There are four or more rows of pale red calli in the centre of the labellum. Flowering occurs from August to early October.

Taxonomy and naming

''Caladenia longicauda'' was first formally described by

John Lindley John Lindley FRS (5 February 1799 – 1 November 1865) was an English botanist, gardener and orchidologist. Early years Born in Catton, near Norwich, England, John Lindley was one of four children of George and Mary Lindley. George Lindley w ...

in 1840 and the description was published in ''

A Sketch of the Vegetation of the Swan River Colony "A Sketch of the Vegetation of the Swan River Colony", also known by its standard botanical abbreviation ''Sketch Veg. Swan R.'', is an 1839 article by John Lindley on the flora of the Swan River Colony. Nearly 300 new species were published in it, ...

''. In 2001

Stephen Hopper Stephen Donald Hopper AC FLS FTSE (born 18 June 1951) is a Western Australian botanist. He graduated in Biology, specialising in conservation biology and vascular plants. Hopper has written eight books, and has over 200 publications to his n ...

and Andrew Brown described eleven subspecies, including subspecies ''eminens'' and the descriptions were published in '' Nuytsia''. The subspecies name (''eminens'') is a Latin word meaning “prominent", or "illustrious" referring to the attractiveness of the flowers of this subspecies.

Distribution and habitat

The stark white spider orchid mainly occurs between Tenterden and Jerramungup but is also found as far east as Esperance and as far north as Moora, in the Avon Wheatbelt, Coolgardie, Esperance Plains, Jarrah Forest, Mallee and

Swan Coastal Plain The Swan Coastal Plain in Western Australia is the geographic feature which contains the Swan River as it travels west to the Indian Ocean. The coastal plain continues well beyond the boundaries of the Swan River and its tributaries, as a geol ...

biogeographic regions A biogeographic realm or ecozone is the broadest biogeographic division of Earth's land surface, based on distributional patterns of terrestrial organisms. They are subdivided into bioregions, which are further subdivided into ecoregions. De ...

where it grows in wandoo (''

Eucalyptus wandoo ''Eucalyptus wandoo'', commonly known as wandoo, dooto, warrnt or wornt, is a small to medium-sized tree that is endemic to the southwest of Western Australia. It has smooth bark, lance-shaped adult leaves, flower buds in groups of nine to sev ...

'') and yate (''

Eucalyptus cornuta ''Eucalyptus cornuta'', commonly known as yate, is a tree species, sometimes a mallee and is endemic to the southwest of Western Australia. It has rough, fibrous bark on all or most of its trunk, smooth bark above, mostly lance-shaped adult le ...

'') woodland.

Conservation

''Caladenia longicauda'' subsp. ''eminens'' is classified as "not threatened" by the Western Australian Government

Department of Parks and Wildlife The Department of Parks and Wildlife (DPaW) was the department of the Government of Western Australia responsible for managing lands described in the ''Conservation and Land Management Act 1984'' and implementing the state's conservation and e ...

References

{{Taxonbar, from=Q26205510 longicauda subsp. eminens Endemic orchids of Australia Orchids of Western Australia Plants described in 2001 Taxa named by Stephen Hopper Taxa named by Andrew Phillip Brown