Commonly called "Mosquito orchids" their name is a hint for the flowersize. Their habitats are coastal areas, growing inland but avoiding semi-arid, alpine and sub-alpine regions. The inflorescence arises from a single heart-shaped leaf that hovers above the soil-surface on a stem. The bottom-side of the leaf is normally red to purple and green on the other side. Flowers are small, less than a centimeter in diameter and pollinated by small flies (Acianthus exiguus is self-pollinating). These plants are normally found in shaded spots in high humidity and air-movement. Plants normally occur in dense populations as they multiply via offset tubers on the ends of long stolonoid roots.
Acianthus go dormant as a fleshy tuber to withstand summer heat, they grow actively in autumn and winter. This means flowering in Februari-August in the Southern Hemisphere, if the plants are cultivated in the other side of the world you should create a set-up for winter-culture. Flowering can happen during leaf development (Acianthus apprimus) or after leaf maturity (Acianthus fornicatus).
Species are not very common in culture outside of Australia, but due to their ease of multiplication they are becoming available via tuberbanks. Be aware of the difficulty in determination: all leaves look alike and the plants can only be identified by the flowers. To make things more difficult, there's also the genus Acianthella (previously in Acianthus) with very similar flowers. As a sidenote, the leaf has the property of expanding considerably in size after flowering.

Acianthus have the tendency to rot when overwatered. Use a free-draining mix based on sandy loam or sand and grit. You should take care not to disturb the plants that are emerging from dormancy as shock can easily abort the developing flowers. It's common for a colony to only have a small percentage of flowering plants.

The seedpods swell and move to an upright position after pollination. It takes 8-10 weeks from pollination to seed.

flies of the family Anisopodidae, Sciaridae and Mycetophilidae are attracted by the nectar 1)

Bower, C.C. (2001). Pollination (Acianthus, pp. 69-70), in Pridgeon, A.M., Cribb, P.J., Chase, M.W. and Rasmussen, F.N. (eds), Genera Orchidacearum, vol. 2, Orchidoideae (part one). Oxford University Press, United Kingdom.
Cheeseman. T.F. (1875). On the fertilisation of Acianthus and Cyrtostylis. Transactions of the New Zealand Institute 7: 349-352.
Jones, D. L. (1974). The pollination of Acianthus caudatus R.Br. Victorian Naturalist 91: 272-274.
Jones, D.L. (1991). New taxa of Australian Orchidaceae. Austral. Orch. Res. 1-207.
Jones, D.L. and Clements, M.A. (1987). Reinstatement of the genus Cyrtostylis R.Br. and its relationships with Acianthus R.Br. (Orchidaceae). Lindleyana 2: 156-160.
Jones, D.L. and Clements, M.A. (2004). Acianthella, a new genus in the Acianthus alliance (Orchidaceae). Orchadian 14(7): 330-332.
Jones, D.L., Clements, M.A., Sharma, I.K., Mackenzie, A.M. and Molloy, B.P.J. (2002). Nomenclatural notes arising from studies into the tribe Diurideae (Orchidaceae). Orchadian 13(10): 437-468.
Kores, P.J. (1995). A systematic study of the genus Acianthus (Orchidaceae: Diuridae). Allertonia 7(3): 87-220.
Szlachetko, D.L. (2001). Genera et Species Orchidalium 1. Polish Bot. J. 46(1): 11-26.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Location
Acianthus sinclairii													New Zealand
Acianthus amplexicaulis													Brisbane, Australia
Acianthus caudatus													Brisbane, Australia
Acianthus exsertus													Brisbane, Australia
Acianthus fornicatus													Brisbane, Australia

Detailed data: Aggregated observation dates from the GBIF.org network.
A colored month means an observation in habitat or collection date of a herbarium specimen with flower or inflorescence. The number refers to the year of last observation or collection.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Location
Acianthus caudatus										1951			Australia
Acianthus exsertus				1946			1946						Australia
Acianthus fornicatus				1949	1953	1949							Australia
Acianthus fornicatus var. sinclairii							1953						New Zealand
Acianthus sinclairii						1956							New Zealand

World Checklist for Acianthus. With the permission of the Trustees of the Royal Botanic Gardens, Kew Published on the Internet
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