''Diuris aequalis'', commonly called the buttercup doubletail, is a species of

orchid 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 flowerin ...

which 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 else ...

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

. It has two rolled leaves and spikes of two to five golden-yellow to orange flowers and is classified as "vulnerable".

Description

''Diuris aequalis'' is a

tuber Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growin ...

ous,

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 wid ...

herb, usually growing to a height of . There are two linear leaves arising from the base of the plant, each leaf long, wide and rolled so that the sides of the leaf face each other. There are between two and five golden-yellow to orange flowers arranged on a raceme, usually without spots, each about wide. 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 c ...

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 coine ...

is broadly egg-shaped to almost circular, long, wide above the flower. 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 linear to lance-shaped, long, wide, sickle-shaped and green. The petals are erect, ear-like above the flower, long and wide. The labellum is long, wide and has three lobes, the medial lobe ridged in its centre and has two broad calli about long. Flowering occurs between October and December, following which the leaves die back to be replaced prior to the next flowering.

Taxonomy and naming

''Diuris aequalis'' was first formally described in 1876 by Robert D. FitzGerald from a previously unpublished description by Ferdinand von Mueller. The description was published in Fitzgerald's book, ''Australian Orchids''. The specific epithet (''aequalis'') is a

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word meaning "like", "same" or "uniform".

Distribution and habitat

Buttercup doubletail orchid occurs on the ranges and tablelands of New South Wales between Braidwood and the

Kanangra-Boyd National Park The Kanangra-Boyd National Park is a protected national park that is located in the Central Tablelands region, west of the Southern Highlands and Macarthur regions, in New South Wales, in eastern Australia. The national park is situated app ...

where it grows in forest and low open

woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the ''plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (se ...

with a grassy understory, often on gentle slopes.

Conservation

Only about 200 individual plants of ''D. aequalis'' are known, mostly on roadsides and on agricultural land. It is listed as "Vulnerable" (VU) under the Australian 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). The threats to its survival include land clearing, grazing, road maintenance and illegal rubbish dumping. It was one of the plants targeted in the 2015 Save a Species Walk.

References

{{Taxonbar, from=Q10267366 aequalis Orchids of New South Wales Flora of New South Wales Plants described in 1876