Cyrtostylis

The genus Cyrtostylis, commonly referred to as gnat orchids, comprises a group of flowering plants belonging to the orchid family, Orchidaceae. These orchids are native to the regions of Australia and New Zealand, where they exhibit a distinct terrestrial growth habit. A notable characteristic of Cyrtostylis is its ability to form dense colonies, often consisting of genetically identical individuals, which suggests efficient vegetative propagation.

Botanical Description

Plants within the Cyrtostylis genus are typically terrestrial, perennial, deciduous, and sympodial herbs. They usually possess a few inconspicuous, fine roots and one or two tubers for sustenance and propagation. The most visually striking feature is the single, heart-shaped leaf that grows close to the ground at the base of the flowering stem. The flowering stem itself is slender and bears one to a few flowers. The flowers are generally pale in color and are often described as insect-like. They feature an erect dorsal sepal and spreading lateral sepals and petals, all of which are narrow and lance-shaped, roughly equal in length. The labellum, a key distinguishing part of the flower, is stalkless, oblong, and similar in length to the sepals and petals. It is further characterized by two bead-like glands and two ridges running along its length. The column of the flower is curved and winged, measuring about half the length of the labellum.

Taxonomy and Naming

The genus Cyrtostylis was first formally described by Robert Brown in his publication Prodromus Florae Novae Hollandiae in 1810. He simultaneously described Cyrtostylis reniformis, which became the type species for the genus. The name Cyrtostylis is derived from ancient Greek, with 'kyrtos' meaning 'curved' and 'stylos' referring to the style. This etymology points to the curved column, a consistent feature across all species within the genus.

There is some variation in the number of species recognized for Cyrtostylis. The World Checklist of Selected Plant Families lists five species, while Australian authorities recognize six. This discrepancy often arises from differing interpretations regarding the classification of Cyrtostylis huegelii, which the Checklist considers a synonym of Cyrtostylis reniformis var. huegelii.

Some of the recognized species include:

• Cyrtostylis oblonga Hook.f. (New Zealand)
• Cyrtostylis reniformis R.Br. – common gnat orchid (found across all six Australian states)
• Cyrtostylis robusta D.L.Jones & M.A.Clem. – large gnat orchid (found in South Australia, Western Australia, Tasmania, and Victoria)
• Cyrtostylis rotundifolia Hook.f. (New Zealand)
• Cyrtostylis tenuissima (Nicholls & Goadby) D.L.Jones & M.A.Clem. – dwarf gnat orchid (found in Western Australia)

Cyrtostylis orchids share similarities with those in the genus Acianthus, but they notably lack the long appendage found on the sepals and petals of Acianthus. Additionally, the lateral sepals in Cyrtostylis differ from those in Acianthus.