Luisia

Luisia, commonly known as velvet orchids or 钗子股属 (chai zi gu shu), is a genus of epiphytic or lithophytic orchids in family Orchidaceae. Plants in this genus have flattened roots, long leafy stems, narrow, thick, leathery leaves and short-lived flowers that open sporadically. There are about forty species found from tropical and subtropical Asia to the Western Pacific.
Description.
Orchids in the genus "Luisia" are epiphytic or lithophytic, monopodial herbs with long, fibrous stems and thick, more or less flattened roots. A large number of cylinder-shaped, narrow leathery leaves are arranged along the stems. Up to ten resupinate, usually small, fleshy flowers are arranged on a short, thickened flowering stem and open sporadically. Each flower has a short, curved stalk and petals that are longer than the sepals. The labellum is large and fleshy with an upper epichile separated by a groove from the lower concave hypochile. The labellum has a rigid connection to the column.
Taxonomy and naming.
The genus "Luisia" was first formally described in 1829 by Charles Gaudichaud-Beaupré and the description was published in "Voyage autour du monde fait par ordre du Roi sur les corvettes de S. M. l'Uranie et la Physicienne". The name "Luisia" honours Don Luis de Torres who assisted the French expedition at Guam.
Distribution.
Orchids in the genus "Luisia" occur in Bhutan, China, India, Indochina, Indonesia, Japan, Malaysia, New Guinea the Philippines, Sri Lanka, Thailand, Australia, Micronesia and Melanesia.
Species list.
The following is a list of species of "Luisia" accepted by the World Checklist of Selected Plant Families as at December 2018: