Arachnis (plant)

The genus Arachnis, abbreviated as Arach in horticultural trade, (common name scorpion orchid,^[2][3]) is a member of the orchid family (Orchidaceae), consisting of more than 20 species native to China, India, Southeast Asia, Indonesia, the Philippines, New Guinea, and the Solomon Islands.^[4][5]

Arachnis
Inflorescence detail of Arachnis longisepala
Flowering Arachnis labrosa specimen
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Monocots
Order:	Asparagales
Family:	Orchidaceae
Subfamily:	Epidendroideae
Tribe:	Vandeae
Subtribe:	Aeridinae
Genus:	Arachnis Blume
Type species
Arachnis flos-aeris (L.) Rchb.f.
Synonyms[1]
Arachnanthe Blume Arhynchium Lindl. Armodorum Breda Esmeralda Rchb.f.

Description

Vegetative characteristics

The appearance of the monopodial, epiphytic herbs of the genus Arachnis is characterized by distichously arranged, linear leaves.^[6] The vining plants may grow into a dense thicket.^[7] Arachnis does not produce pseudobulbs.^[8]

Generative characteristics

The flowers are thought to resemble spiders,^[8] and they are fragrant.^[6][8] The fragrance has been described as musky.^[8]

• 
  Arachnis labrosa growing epiphytically on a tree
• 
  Detail of Arachnis labrosa flower
• 
  Botanical illustration of Arachnis clarkei
• 
  Detail of Arachnis cathcartii flower
• 
  Detail of Arachnis flos-aeris flower
• 
  Botanical illustration of Arachnis annamensis

Etymology

The generic epithet Arachnis is derived from the Greek word arachne for spider.^[9]

Ecology

Habitat

Arachnis senapatiana has been found growing in subtropical broad-leaved forests at elevations of 1747 m above sea level.^[6]

Flowering

Arachnis senapatiana is known to flower in June.^[6]

Taxonomy

Accepted species

There are currently 16 accepted species, including one natural hybrid:^[1]

• Arachnis annamensis (Rolfe) J.J.Sm.
• Arachnis bella (Rchb.f.) J.J.Sm.
• Arachnis bouffordii Ormerod
• Arachnis calcarata Holttum
• Arachnis cathcartii (Lindl.) J.J.Sm.
• Arachnis clarkei (Rchb.f.) J.J.Sm.
• Arachnis flos-aeris (L.) Rchb.f.
• Arachnis grandisepala J.J.Wood
• Arachnis hookeriana (Rchb.f.) Rchb.f.
• Arachnis labrosa (Lindl. & Paxton) Rchb.f.
• Arachnis limax Seidenf.
• Arachnis longisepala (J.J.Wood) Shim & A.Lamb
• Arachnis × maingayi (Hook.f.) Schltr.
• Arachnis senapatiana (Phukan & A.A.Mao) Kocyan & Schuit.
• Arachnis seramensis (Ormerod) R.Rice
• Arachnis siamensis (Schltr.) Tang & F.T.Wang
• Arachnis sulingi (Blume) Rchb.f.

Species formerly placed in Arachnis

• Arachnis beccarii Rchb.f. is now considered to be Dimorphorchis beccarii (Rchb.f.) Kocyan & Schuit.^[10]
• Arachnis breviscapa (J.J.Sm.) J.J.Sm. is now considered to be Dimorphorchis breviscapa (J.J.Sm.) Kocyan & Schuit.^[11]
• Arachnis celebica (Schltr.) J.J.Sm. is now considered to be Dimorphorchis celebica (Schltr.) Ormerod^[12]
• Arachnis imthurnii (Rolfe) L.O.Williams is now considered to be Dimorphorchis beccarii var. imthurnii (Rolfe) Kocyan & Schuit.^[13]
• Arachnis longicaulis (Schltr.) L.O.Williams is now considered to be Dimorphorchis breviscapa (J.J.Sm.) Kocyan & Schuit.^[11]
• Arachnis lowii (Lindl.) Rchb.f. is now considered to be Dimorphorchis lowii (Lindl.) Rolfe^[14]
• Arachnis lyonii Ames is now considered to be Dimorphorchis lyonii (Ames) Ormerod^[15]
• Arachnis muelleri (Kraenzl.) J.J.Sm. is now considered to be Dimorphorchis beccarii var. beccarii^[16]
• Arachnis philippinensis (Lindl.) Ames is now considered to be Trichoglottis philippinensis Lindl.^[17]
• Arachnis rohaniana (Rchb.f.) Rchb.f. is now considered to be Dimorphorchis rohaniana (Rchb.f.) P.J.Cribb^[18]
• Arachnis beccarii var. imthurnii (Rolfe) K.W.Tan is now considered to be Dimorphorchis beccarii var. imthurnii (Rolfe) Kocyan & Schuit.^[19]
• Arachnis longicaulis f. flavescens Valmayor & D.Tiu is now considered to be Dimorphorchis breviscapa (J.J.Sm.) Kocyan & Schuit.^[11]

Conservation

Arachnis has become extinct in Nansei-shoto.^[1]

Horticulture

It can be cultivated under warm and moist conditions growing in pots, baskets, or mounted on slabs.^[7]

References

1. "Arachnis Blume". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 January 2022.
2. Beard, James Daniel (2015). "A Translator's Vietnamese English Dictionary of Plant Names" (PDF). monash.edu.au. Archived from the original (PDF) on 21 December 2016. Retrieved 17 December 2016.
3. Yearron, Sydney H. "Scientific or Latin Names to English Common Name" (PDF). The Canadian Orchid Congress. Retrieved 21 December 2016.
4. Kew World Checklist of Selected Plant Families
5. Flora of China, v25 p 465, 蜘蛛兰属 zhi zhu lan shu , Arachnis
6. Jakha, H. Y., Deb, C. R., Dey, S., & Jamir, N. S. (2014). "Arachnis senapatiana (Phukan & AA Mao) Kocyan & Schuiteman (Orchidaceae): an addition to the flora of Nagaland, India." Pleione, 8(2), 516-518.
7. Rach, N. (n.d.). Arachnis  Blume 1825. American Orchid Society. Retrieved January 6, 2023, from https://www.aos.org/orchids/orchids-a-to-z/letter-a/arachnis.aspx
8. Tan, K. W. (1974). "Taxonomy of Arachnis, Armodorum, Esmeralda and Dimorphorchis (Orchidaceae)." University of Miami.
9. Teoh, E.S. (2021). Arachnis Bl.. In: Orchid Species from Himalaya and Southeast Asia Vol. 1 (A - E). Springer, Cham. https://doi.org/10.1007/978-3-030-58872-4_15
10. "Dimorphorchis beccarii (Rchb.f.) Kocyan & Schuit". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 January 2022.
11. "Dimorphorchis breviscapa (J.J.Sm.) Kocyan & Schuit". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 January 2022.
12. "Dimorphorchis celebica (Schltr.) Ormerod". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 January 2022.
13. "Dimorphorchis beccarii var. imthurnii (Rolfe) Kocyan & Schuit". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 January 2022.
14. "Dimorphorchis lowii (Lindl.) Rolfe". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 January 2022.
15. "Dimorphorchis lyonii (Ames) Ormerod". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 January 2022.
16. "Dimorphorchis beccarii var. beccarii". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 January 2022.
17. "Trichoglottis philippinensis Lindl". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 January 2022.
18. "Dimorphorchis rohaniana (Rchb.f.) P.J.Cribb". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 January 2022.
19. "Dimorphorchis beccarii var. imthurnii (Rolfe) Kocyan & Schuit". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 January 2022.

External links

• Media related to Arachnis (Orchidaceae) at Wikimedia Commons
• Data related to Arachnis at Wikispecies