Arthrochilus
Arthrochilus
Arthrochilus, commonly known as elbow orchids, is a genus of approximately fifteen flowering plant species native to Australia and New Guinea. These orchids are distinguished by their unique pollination mechanism, where male thynnid wasps attempt to mate with the flower, becoming trapped by hooked wings while pollinia are transferred.
Key Facts
- ›Arthrochilus orchids are terrestrial plants found in Australia and New Guinea.
- ›Their flowers are pollinated by male thynnid wasps through a pseudocopulation process.
- ›The labellum of the flower mimics a female thynnid wasp, attracting male wasps.
- ›Hook-like wings on the column hold the wasp in place for pollinia transfer.
- ›The genus name "Arthrochilus" refers to the jointed lip of the flower.
- ›Most species are found in tropical regions, flowering during the summer wet season.
Elbow Orchids
Terrestrial
Dull-Coloured
Summer
Male Thynnid Wasps
About Arthrochilus
Arthrochilus: The Elbow Orchids
Arthrochilus, commonly referred to as elbow orchids, is a genus comprising approximately fifteen species of flowering plants within the Orchidaceae family. These unique orchids are found in Australia and New Guinea, with the majority of species inhabiting tropical regions. Arthrochilus orchids are characterized by their terrestrial growth habit, meaning they grow in soil rather than on trees or rocks.
Pollination Mechanism
The most distinctive feature of Arthrochilus orchids is their specialized pollination method, which relies on male thynnid wasps. The flower's labellum is highly modified to mimic a wingless female thynnid wasp, complete with feathery cilia and club-shaped structures. When a male wasp attempts to mate with this floral mimic, it is drawn head-first against the column. The column possesses two pairs of wings; two smaller wings surround the reproductive organs, while two larger, hook-like wings effectively restrain the wasp. This unique mechanism ensures that the pollinia (pollen masses) adhere to the wasp's back. If the wasp is already carrying pollinia from another flower, they are then crushed against the stigma, facilitating cross-pollination. In some tropical species, the wasps struggle so vigorously that the labellum can be torn off.
Description and Habitat
These perennial, deciduous herbs typically possess a few inconspicuous, fine roots and a single oval-shaped tuber that lacks a protective fibrous sheath. Some species exhibit colonial behavior, reproducing asexually through daughter tubers formed on root-like stolons. The stems are short, erect, and unbranched, bearing thin, leaf-like cataphylls at each node. Up to six leaves are usually found at or near the base of the plant, sometimes forming a rosette. The inflorescences are racemes bearing a few to many non-resupinate, dull-colored flowers on wiry stalks. The dorsal sepal is typically similar to or larger than the lateral sepals, with its sides curving inward. The lateral sepals and petals are attached to the base of the column, with the petals being smaller than the sepals. The scientific name "Arthrochilus" itself derives from the Ancient Greek words 'arthron' (joint) and 'cheilos' (lip), referencing the jointed nature of the labellum.
Distribution
Elbow orchids are found in all Australian states except Western Australia, as well as in southern Papua New Guinea and on the Torres Strait Islands. Tropical species typically grow and flower during the summer wet season, often in sandy soils within forest or woodland environments. A subspecies, nothofagicola, is found in Tasmania.
Source: Wikipedia ↗
Frequently Asked Questions
What are Arthrochilus orchids?
Arthrochilus, commonly called elbow orchids, is a genus of about fifteen species of flowering plants belonging to the Orchidaceae family. They are primarily found in Australia and New Guinea.
How do Arthrochilus orchids get pollinated?
Arthrochilus orchids employ a fascinating pollination strategy involving male thynnid wasps. The flower's labellum mimics a wingless female wasp, and when a male wasp attempts to mate with it, hooked wings on the column trap the insect long enough for pollen to be transferred.
What is unique about the Arthrochilus flower structure?
The most distinctive feature is the highly modified labellum, adorned with feathery cilia and club-shaped structures, resembling a female thynnid wasp. Additionally, the column possesses hook-like wings that restrain the pollinating wasp during the process.
Where are elbow orchids found?
Elbow orchids are distributed across Australia, excluding Western Australia, and in southern Papua New Guinea, including the Torres Strait Islands. While most species prefer tropical regions, some, like A. huntianus, are found in eastern Australia and Tasmania.
What is the meaning of the scientific name Arthrochilus?
The scientific name Arthrochilus is derived from Ancient Greek words. 'Arthron' means 'joint,' and 'cheilos' means 'lip,' referring to the characteristic jointed structure of the orchid's labellum.
Related Orchid species
Corymborkis
Corymborkis is a genus of terrestrial orchids found across tropical regions worldwide. These evergreen plants are known for their leafy stems, pleated leaves, and widely-opening flowers, which are typically greenish-white and arranged in crowded clusters. The genus name itself reflects the characteristic bunched arrangement of their blooms.
Anoectochilus
Anoectochilus, commonly known as marbled jewel orchids or filigree orchids, is a genus of approximately fifty terrestrial orchid species found in moist, deeply shaded areas across the Himalayas, Southeast Asia, and the Pacific Islands. These orchids are distinctive for their dark leaves adorned with striking silvery or reddish veins and their relatively large, velvety flowers with a uniquely structured labellum.
Calochilus
Calochilus, commonly known as beard orchids, is a genus of approximately 30 terrestrial orchid species belonging to the family Orchidaceae. These orchids are distinctive for their densely hairy labellum, which gives them their common name. Primarily found in Australia, with some species extending to New Zealand, New Guinea, and New Caledonia, they are terrestrial herbs that typically have a single leaf or are leafless, and reproduce through self-pollination if cross-pollination fails.