(pronounced: ah-RACK-niss)


Vandeae subtribe Aeridinae

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Large climbing, vining, monopodial epiphytes rooting along the stems. Leaves alternate, distichous, oblong, leathery, basally clasping the stem. Inflorescences short to elongate lateral racemes or panicles. Flowers few to many, showy, fleshy-rigid, usually fragrant. Sepals and petals subequal, free, the dorsal sepal stiffly erect, usually with revolute lateral margins, the petals and lateral sepals often falcate. Lip three-lobed, fleshy, hinged to a fleshy column foot, with a short broad spur, with a central fleshy callus. Column lightly arching, stout; pollinia 4, in 2 unequal pairs, on a stipe and viscidium.


From the Greek arachne, meaning spider, in allusion to the flowers resemblance to spiders.


A genus of 13 species distributed from Indochina to New Guinea. Common name: Scorpion Orchid.

Care and Culture Card

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Holttum, R. E. 1949. The Malayan Scorpion orchids (genus Arachnis). Malayan Nat. J. 4(2):85-92.

Lamb, A. 1982. The scorpion orchids of Sabah. Orchid Digest 46(5):175-186.

Smith, J. J. 1912. Arachnis Bl. und Vandopsis Pfitz. Natuurk. Tijdschr. Ned. Ind. 72:71-78.

Tan, K. 1975. Taxonomy of Arachnis, Armodorum, Esmeralda and Dimorphorchis (Orchidaceae). Selbyana 1:1-15.