''Diuris amplissima'', commonly known as giant donkey orchid, 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 ...

that 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 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 ...

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

. It is a rare species and the largest ''Diuris'' in Western Australia. It has two or three leaves at its base and up to seven purple and dull yellowish-brown flowers on a tall flowering stem.

Description

''Diuris amplissima'' 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 ...

, usually growing to a height of with two or three leaves emerging at the base, each leaf long and wide. There are between three and seven purple and dull yellowish-brown flowers long and wide. The dorsal sepal is erect, long and wide and oval to kidney-shaped (wider than long). The lateral sepals are linear to sword-shaped, green with purplish marks, long, wide, turned downwards and usually parallel to 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 with an elliptic to oval blade long and wide on a purplish-brown stalk long. The labellum is long and has three lobes. The centre lobe is wedge-shaped, long, wide and the side lobes are asymmetric egg-shaped, long and wide with wavy or crinkled edges. There is a ridge-like callus in the mid-line of the base of the labellum. Flowering occurs from September to November.

Taxonomy and naming

''Diuris amplissima'' was first formally described in 1991 by David Jones from a specimen collected near Moodiarrup, and the description was published in ''Australian Orchid Review''. 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 ...

(''amplissima'') 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 "largest", referring to the "impressive flowers".

Distribution and habitat

Giant donkey orchid grows in woodland and forest between Porongurup and

Capel Capel may refer to: People *Capell, surname, includes a list of people with the surnames Capel and Capell *Capel (given name), includes a list of people with the given name Capel Places England *Capel, Kent, a village and civil parish near T ...

in the Avon Wheatbelt,

Jarrah Forest Jarrah forest is tall open forest in which the dominant overstory tree is ''Eucalyptus marginata'' (jarrah). The ecosystem occurs only in the Southwest Botanical Province of Western Australia. It is most common in the biogeographic region named in ...

and Mallee

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 ...

. It is a rare species, similar to '' D. magnifica'' but grows in heavier soils than the sandy habitat of that species.

Conservation

''Diuris amplissima'' 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=Q10267368 amplissima Endemic orchids of Australia Orchids of Western Australia Endemic flora of Western Australia Plants described in 1991 Taxa named by David L. Jones (botanist)