Acianthus

Acianthus
	Acianthus caudatus
Systematics
Order :	Asparagales (Asparagales)
Family :	Orchids (orchidaceae)
Subfamily :	Orchidoideae
Tribe :	Diurideae
Sub tribus :	Acianthinae
Genre :	Acianthus
Scientific name
	Acianthus
	Hook.f.

The plant genus acianthus belongs to the family of orchids (Orchidaceae). The approximately 22 species are distributed in eastern Australia , New Zealand and New Caledonia .

Description and ecology

Illustration of Acianthus amplexicaulis

The Acianthus species are small, perennial herbaceous plants . As a survival organ, they have an underground tuber , which is replaced annually by a new one that arises on a short rhizome . In addition, other daughter tubers can develop on root-like runners, which are used for vegetative reproduction. There are no roots . The sprout axis arises from the tuber with only one leaf . The petiole is fused with the stem axis, the leaf is unfolded horizontally directly above the ground. The leaf blade is quite broad and short, rarely up to twice as long as it is wide.

The stem axis continues above the foliage leaf as a racemose inflorescence . The flowers are small, stalked, resupinated and not conspicuously colored. The hermaphrodite flowers are zygomorphic and threefold. The bracts are not grown together. The sepals are formed every three equal depending on the type or the top is substantially wider than the lateral. The petals are the same size or smaller than the outer petals. The lip is fused with the base for a short distance with the column . The lip is not lobed, it ends pointed. A more or less large callus sits on the lip, two glands can sit at the base, some species produce nectar. The column is slender and curved. At the top it bears the two-chambered stamen with four pollinia . These all hang on a common adhesive disc (Viscidium) or two each on an adhesive disc. The capsule fruit contains numerous winged seeds.

Many species are pollinated by small flies from the families Anisopodidae , Sciaridae and Mycetophilidae , which are attracted by the nectar .

Acianthus - distribution area

Occurrence

The species of the genus Acianthus are distributed in eastern Australia, Tasmania, New Caledonia, the North and South Island of New Zealand, on Stewart Island , Chatham Island and the Kermadec Islands . They mostly occur in shady, wooded areas that do not show any drought, at least in the growing season. They colonize altitudes up to 1100 meters.

Acianthus exsertus

Acianthus fornicatus

Systematics and botanical history

The genus Acianthus is classified in the subtribe Acianthinae within the orchid family. It was set up in 1810 by Robert Brown . He described three species that are similar in their column without lateral widening, the number of pollinia and their pointed sepals. The generic name is made up of the Greek words ἀκίς akis , "tip", and ἄνθος anthos , "blossom", and refers to these pointed petals. Type species is Acianthus exsertus R.Br.

There are from 8 to 21 species in the genus Acianthus :

Acianthus aegeridantennatus N.Hallé : It occurs in New Caledonia. It is also called the Stigmatodactylus aegeridantennatus (N.Hallé) MAClem. & DLJones placed in the genus Stigmatostylis .
Acianthus amplexicaulis (FMBailey) Rolfe : It occurs in Queensland, New South Wales and New Caledonia.
Acianthus atepalus Rchb. f. : It occurs in southeastern New Caledonia. It is also called Townsonia atepala (Rchb.f.) MAClem. & DLJones placed in a different genre.
Acianthus bracteatus Rendle : It occurs in southeastern New Caledonia. It is also called the Stigmatodactylus bracteatus (Rendle) MAClem. & DLJones placed in a different genre.
Acianthus caudatus R.Br. : It occurs in southeastern Australia.
Acianthus confusus Guillaumin : It occurs in New Caledonia. It is also called Stigmatodactylus confusus (Guillaumin) MAClem. & DLJones placed in the genus Stigmatostylis .
Acianthus corniculatus Rendle : It occurs in northwestern New Caledonia. It is also called Stigmatodactylus corniculatus (Rendle) MAClem. & DLJones placed in the genus Stigmatostylis .
Acianthus cuneatus D.L. Jones & LMCopel. : The species first described in 2017 occurs in New South Wales.
Acianthus cymbalariifolius F. Muell. & Kraenzl. : It occurs in New Caledonia. It is also called Stigmatodactylus cymbalariifolius (F.Muell. & Kraenzl.) MAClem. & DLJones placed in the genus Stigmatostylis .
Acianthus elegans Rchb. f. : It occurs in New Caledonia. It is also called Stigmatodactylus elegans (Rchb.f.) MAClem. & DLJones placed in the genus Stigmatostylis .
Acianthus exsertus R.Br. : It occurs in eastern and south-eastern Australia.
Acianthus fornicatus R.Br. (Syn .: acianthus Apprimus D.L.Jones ): It occurs in eastern Australia.
Acianthus grandiflorus Schltr. : It occurs in New Caledonia. It is also called Stigmatodactylus grandiflorus (Schltr.) MAClem. & DLJones placed in the genus Stigmatostylis .
Acianthus halleanus Kores : It occurs in New Caledonia. It is also called the Stigmatodactylus halleanus (Kores) MAClem. & DLJones placed in the genus Stigmatostylis .
Acianthus heptadactylus Kraenzl. : It occurs in New Caledonia. It is also called Stigmatodactylus heptadactylus (Kraenzl.) MAClem. & DLJones placed in the genus Stigmatostylis .
Acianthus ledwardii Rupp : It occurs in southeastern Queensland.
Acianthus macroglossus Schltr. : It occurs in southeastern New Caledonia. It is also called Stigmatodactylus macroglossus (Schltr.) MAClem. & DLJones placed in the genus Stigmatostylis .
Acianthus oxyglossus Schltr. : It occurs in southeastern New Caledonia. It is also called Stigmatodactylus oxyglossus (Schltr.) MAClem. & DLJones placed in the genus Stigmatostylis .
Acianthus saxatilis D.L. Jones & MAClem. : The species first described in 2014 occurs in Queensland.
Acianthus sinclairii Hook. f. : It occurs in New Zealand, on Stewart Island , on the Chatham Islands and on the Kermadec Islands .
Acianthus tenuilabris Schltr. : It occurs in New Caledonia. It is also called Stigmatodactylus tenuilabris (Schltr.) MAClem. & DLJones placed in the genus Stigmatostylis .
Acianthus veillonis N. Hallé : It occurs in southeastern New Caledonia.

No longer counted in this genus:

Acianthus viridis Hook. f. => Townsonia viridis (Hook.f.) Schltr.

Individual evidence

↑ ^a ^b ^c ^d ^e Alec M. Pridgeon, Phillip J. Cribb, Mark W. Chase, Finn N. Rasmussen (eds.): Genera Orchidacearum. Orchidoideae (Part 1) . tape 2 . Oxford University Press, New York and Oxford 2001, ISBN 0-19-850710-0 , pp. 68-70 .
↑ ^a ^b L. B. Moore, E. Edgar (1970): Flora of New Zealand . Volume II. Indigenous Tracheophyta - Monocotyledons except Graminae . First electronic edition, Landcare Research, June 2004. Transcr. AD Wilton, IML Andres. Flora of New Zealand
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y Rafaël Govaerts (Ed.): Acianthus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 3, 2020.
^ In: Prodromus Florae Novae Hollandiae . 1810, p. 321.

Web links

Commons : Acianthus - album with pictures, videos and audio files

DL Jones, T. Hopley, SM Duffy, KJ Richards, MA Clements, X. Zhang (2006): Australian Orchid Genera .
New Zealand Plant Conservation Network ( Memento of October 16, 2008 in the Internet Archive )

[Pridgeon2001-1] Alec M. Pridgeon, Phillip J. Cribb, Mark W. Chase, Finn N. Rasmussen (eds.): Genera Orchidacearum. Orchidoideae (Part 1) . tape 2 . Oxford University Press, New York and Oxford 2001, ISBN 0-19-850710-0 , pp. 68-70 .

[FNZ-2] L. B. Moore, E. Edgar (1970): Flora of New Zealand . Volume II. Indigenous Tracheophyta - Monocotyledons except Graminae . First electronic edition, Landcare Research, June 2004. Transcr. AD Wilton, IML Andres. Flora of New Zealand

[WCSP-3] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y Rafaël Govaerts (Ed.): Acianthus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 3, 2020.

[4] In: Prodromus Florae Novae Hollandiae . 1810, p. 321.