''Arthrochilus latipes'', commonly known as robust elbow orchid, is a

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

in the

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 ...

family (Orchidaceae) 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 elsew ...

to the "

Top End The Top End of Australia's Northern Territory is a geographical region encompassing the northernmost section of the Northern Territory, which aside from the Cape York Peninsula is the northernmost part of the Australian continent. It covers a ra ...

" of the

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...

in Australia. Each plant has from two to four ground-hugging leaves and between three and fifteen flowers during the

wet season The wet season (sometimes called the Rainy season) is the time of year when most of a region's average annual rainfall occurs. It is the time of year where the majority of a country's or region's annual precipitation occurs. Generally, the sea ...

and the species often forms spreading colonies on sandstone escarpments. Like others in the genus, the flowers are pollinated by a species of thynnid

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. Th ...

Description

''Arthrochilus latipes'' 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, aft ...

sympodial Sympodial growth is a bifurcating branching pattern where one branch develops more strongly than the other, resulting in the stronger branches forming the primary shoot and the weaker branches appearing laterally. A sympodium, also referred to 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 medicinal ...

with an underground tuber which produces daughter tubers on the end of root-like

stolon In biology, stolons (from Latin '' stolō'', genitive ''stolōnis'' – "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external s ...

s. There are two to four lance-shaped, ground-hugging, dull green leaves at the base of the plant, each leaf long and wide. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is a

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

, tall with three to about fifteen flowers, each long with and green with brownish

glands In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). Structure De ...

on the labellum. 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 coined b ...

curves downwards, is narrow egg-shaped to spoon-shaped, about long, wide and is wrapped around one-quarter of 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. ...

. 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 cons ...

sepals and petals are turned back towards the ovary, the sepals about and the petals about the same length but narrower. The labellum is about but wider at the base, greenish with a dark purple blotch at its base. The

callus A callus is an area of thickened and sometimes hardened skin that forms as a response to repeated friction, pressure, or other irritation. Since repeated contact is required, calluses are most often found on the feet and hands, but they may o ...

resembles a flightless female thynnid wasp and is covered with short, shiny, club-shaped, yellowish brown to brown structures called "calli". The tip of the callus is bulb-shaped and covered with shiny black glands. The column is shaped like a semi-circle, about long with its inner surface hairy. One pair of column wings are triangular and point forwards, while the other pair on the side of the column are erect and have a hooked summit. Flowering occurs from October to January and is followed by a

dehiscent Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part; structures that op ...

, oval-shaped capsule about long.

Taxonomy and naming

''Arthrochilus latipes'' was first formally described in 1991 by David Jones and the description was published in ''Australian Orchid Research'' from a specimen collected in Radon Gorge in

Kakadu National Park Kakadu National Park is a protected area in the Northern Territory of Australia, southeast of Darwin. It is a World Heritage Site. Kakadu is also gazetted as a locality, covering the same area as the national park, with 313 people recorded liv ...

. 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 ...

(''latipes'') is derived from the

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 ...

words ''latus'' meaning "broad" and ''pes'' meaning "foot" referring to the broad base of the labellum of this orchid species.

Distribution and habitat

Robust elbow orchid is found in the Top End of the Northern Territory, east of Darwin, growing on rocky outcrops and sandstone escarpments, especially in the Kakadu and Litchfield National Parks.

Ecology

As with other ''Arthrochilus'' orchids, robust elbow orchid is pollinated by males thynnid wasps of the genus '' Arthrothynnus'' although the species involved is not known. It also reproduces asexually by producing new tubers.

References

{{Taxonbar, from=Q15490660

latipes ''Latipes'' is a genus of air-breathing land slugs, terrestrial pulmonate gastropod mollusks in the family Veronicellidae, the leatherleaf slugs. Species Species within the genus ''Latipes'' include: * ''Latipes pterocaulis ''Latipes'' i ...

Plants described in 1991 Orchids of the Northern Territory