''Caladenia argocalla'', commonly known as white beauty spider orchid, is a plant in the orchid family

Orchidaceae Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

and is

endemic Endemism is the state of a species being found 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 found els ...

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

. It is a ground orchid which grows singly or in loose groups and has a single, hairy leaf and one or two white to greenish-white flowers on a wiry, hairy stalk. The total population is thought to be between 2,000 and 4,500 and it is classed as an "Endangered" species.

Description

''Caladenia argocalla'' is a terrestrial,

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, a ...

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 medicina ...

with an underground tuber and a single hairy, linear to narrow lance-shaped leaf. The leaf is erect, long, wide and dull green. The leaf appears in April or May but leaves or flowers do not appear every year, the number of flowering plants fluctuating from year to year. One or two unscented flowers are borne on a wiry, hairy spike high. The flowers are about in diameter and are white or greenish-white with a narrow stripe along the

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined ...

s and

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

s. The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

is long, about wide, linear to elliptic in shape but narrows to a thin, thread-like end about wide. The

lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction * Lateral cricoarytenoid muscle * Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral co ...

sepals are long, about wide, egg-shaped to lance-shaped in the lower part but taper to a long thin thread-like end. The

s are long, about wide and have a similar shape to the sepals. The labellum is egg-shaped to heart-shaped, erect near its base but curves forward, especially towards its end. There are ten to twelve white or purplish calli up to long along the edges of the labellum and six to eight rows of red or white golf-club shaped calli in the centre and extending almost to the tip of the labellum. 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 long and transparent with reddish stripes and other shapes as well as broad wings. Flowering occurs from September to October.

Taxonomy and naming

''Caladenia argocalla'' was first formally described by David L. Jones in 1991 and the description was published in ''Australian Orchid Research''. The

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Ty ...

specimen was collected near

Kapunda Kapunda is a town on the Light River and near the Barossa Valley in South Australia. It was established after a discovery in 1842 of significant copper deposits. The population was 2,917 at the 2016 Australian census. The southern entrance ...

. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

(''argocalla'') is derived from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

words ''argos'' meaning "white" and ''kallos'' meaning "beautiful" in reference to the common name.

Distribution and habitat

White beauty spider orchid grows on hills and slopes in forest, usually with sheoaks. It is only known from thirteen subpopulations in the hills north of

Adelaide Adelaide ( ) is the list of Australian capital cities, capital city of South Australia, the state's largest city and the list of cities in Australia by population, fifth-most populous city in Australia. "Adelaide" may refer to either Greater A ...

, including in the

Spring Gully Conservation Park Spring Gully Conservation Park, formerly the Spring Gully National Park), is a protected area located in the Australian state of South Australia in the localities of Sevenhills and Spring Gully about south of the town centre in Clare. The ...

Conservation

The total size of the population of this species in 2006 was estimated to be between 2,000 and 4,500 individuals. The main threats to its survival are considered to be habitat degradation, weed invasion, lack of pollinators and grazing by native, domestic and feral animals. It is classified as "Endangered" under the South Australian ''

National Parks and Wildlife Act 1972 Protected areas of South Australia consists of protected areas located within South Australia and its immediate onshore waters and which are managed by South Australian Government agencies. As of March 2018, South Australia contains 359 separ ...

'' and the Commonwealth Government ''

Environment Protection and Biodiversity Conservation Act 1999 The ''Environment Protection and Biodiversity Conservation Act 1999'' (Cth) is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and cult ...

'' (EPBC) Act.

References

{{Taxonbar, from=Q15287475 aestiva Plants described in 1991 Endemic orchids of Australia Orchids of South Australia Taxa named by David L. Jones (botanist)