''Diuris flavescens'', commonly called the pale yellow doubletail or Wingham 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 flowering ...

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 elsew ...

to a small area in

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 linear leaves at its base and up to five pale yellow flowers with dark brown markings. Fewer than 200 plants survive in grassy forest near Wingham.

Description

''Diuris flavescens'' 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 growing ...

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 wide ...

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 two linear leaves long, wide and folded lengthwise. Up to five pale yellow flowers with dark brown markings, wide are borne on a flowering stem tall. The dorsal sepal projects forward and is narrow egg-shaped, long and wide. It is yellow with greenish brown and reddish brown blotches. The lateral sepals are lance-shaped with the narrower end towards the base, green and brown, long, wide, turned downwards and parallel to, or crossed over each other. The

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 are more or less erect, spread apart from each other with an elliptic to almost circular blade long and wide on a curved, green to brown stalk long. The labellum is long and has three lobes. The centre lobe is egg-shaped, wide with reddish brown markings and folded lengthwise. The side lobes are linear to narrow egg-shaped, long and about wide. There are two ridge-like calli about long near the base of the mid-line of the base of the labellum. Flowering occurs in September and October.

Taxonomy and naming

''Diuris flavescens'' was first formally described in 1991 by David Jones from a specimen collected south-east of Wingham and the description was published in ''Australian Orchid Research''. 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 ...

(''flavescens'') 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 "pale yellow", referring to the colour of the flowers of this species.

Distribution and habitat

The pale yellow doubletail grows in grassy forest in the Wingham district.

Conservation

''Diuris flavescens'' is classified as "critically endangered" under the Australian government '' Environment Protection and Biodiversity Conservation Act 1999'' and the New South Wales '' Biodiversity Conservation Act 2016''. The main threats to the species are illegal collecting, weed invasion and habitat disturbance. The staff at the Australian Botanic Garden Mount Annan are working to secure the future of the species by growing it from collected seed with the fungus required by the orchid.

References

{{Taxonbar, from=Q10267390 flavescens Endemic orchids of Australia Orchids of New South Wales Plants described in 1991 Taxa named by David L. Jones (botanist)