Coelogyne Lindl. 1821, is a genus of over 200 sympodial epiphytes from the family Orchidaceae, distributed across India, China, Indonesia and the Fiji islands, with the main centers in Borneo, Sumatra and the Himalayas. They can be found from tropical lowland forests to montane rainforests. A few species grow as terrestrials or even as lithophytes in open, humid habitats. The genera BolborchisLindl., Hologyne Pfitzer and Ptychogyne Pfitzer are generally included here. The genus is abbreviated Coel in trade journals.
The wide distribution of this genus has resulted in a wide variety of temperature variation from species to species, some requiring cool to cold conditions to grow and bloom reliably, while others need decidedly warmer temperatures to achieve the same.
The scientific name is derived from the Greek words koilos (hollow) and gyne (woman), referring to the concave stigma.
This genus lacks the saccate base of the labellum, a typical characteristic which is present in the other genera in the subtribe Coelogyninae. The free lip has high lateral lobes along the basal part of the labellum (hypochile) and smooth, toothed or warty keels.
The pseudobulbs of one internode vary in size. They may be closely or widely spaced through sympodial growth along the rhizome.
Inflorescences often show a small to very large number of showy, medium-sized to large flowers. They may arise either from the apex of the newly completed pseudobulb at the end of the growing season (as in Coelogyne fimbriata), or may precede the new growth in early spring (as in Coelogyne cristata). The typical colour range of this genus is white, through tawny brown to green, and occasionally peachy tones. All species have four pollinia.
They have often a sweet scent, attracting different kinds of pollinators, such as bees, wasps and beetles.
A few species are commonly known as 'necklace orchids', because of their long, pendant, multi-flowered inflorescence.
The cooler growing species such as Coelogyne fimbriata, Coelogyne ovalis, Colegyne fuliginosa, Coelogyne cristata, Coelogyne flaccida, Coelogyne nitida originate in the Himalayan region of India and southeast Asia. They require a decided rest period during winter during which they receive no feed, very little water (enough to prevent pseudobulbs shrivelling), cool to cold temperatures and high light. These conditions seem to aid flowering in spring for some growers, though others report that more constant conditions can also produce regular flowering.
Coelogyne has never become very popular among orchid growers and has even been ignored. However there is now a growing number of man-made hybrids, such as :
Coelogyne 'Mem. W. Micholitz' (C. mooreana × C. lawrenceana)
Coelogyne 'Linda Buckley' (C. mooreana × C. cristata)
Coelogyne 'Burfordiensis' (C. pandurata × C. asperata).
Coelogyne 'South Carolina' (C. pandurata x C. Burfordiense), sometimes called "the black orchid" because of the black coloration of the heavily patterned and structured lip.
The traditional taxonomy of the genus Coelogyne is still disputed. Coelogyne has been subdivided in 23 sections or subgenera by De Vogel (1994) and Clayton. Molecular data however show that Coelogyne is paraphyletic and should be reorganised, according to the study by Barbara Gravendeel et al. given in the reference works here below :
Coelogyne should include the genera Neogyna and Pholidota
the following sections should be removed from Coelogyne : sections Coelogyne (in part), Cyathogyne, Tomentosae, Rigidiformes, Veitchiae and Verrucosae.
This new genus Coelogyne should then contain about 160 species.
The database IPNI gives 415 entries for this genus, but a large number are invalid or have become synonyms. These are not mentioned in the following traditional list.
Coelogyne acutilabium de Vogel
Coelogyne albobrunnea J.J.Sm.
Coelogyne albolutea Rolfe
Coelogyne anceps Hook.f.
Coelogyne asperata Lindl.
Coelogyne assamica Linden & Rchb.f.
Coelogyne barbata Lindl. ex Griff.
Coelogyne beccarii Rchb.f.
Coelogyne bicamerata J.J.Sm.
Coelogyne bilamellata Lindl.
Coelogyne borneensis Rolfe
Coelogyne brachygyne J.J.Sm.
Coelogyne brachyptera Rchb.f.
Coelogyne breviscapa Lindl.
Coelogyne bruneiensis de Vogel
Coelogyne buennemeyeri J.J.Sm.
Coelogyne calcarata J.J.Sm.
Coelogyne calcicola Kerr
Coelogyne caloglossa Schltr.
Coelogyne candoonensis Ames
Coelogyne carinata Rolfe.
Coelogyne celebensis J.J.Sm.
Coelogyne chanii Gravend. & de Vogel
Coelogyne chlorophaea Schltr.
Coelogyne chloroptera Rchb.f.
Coelogyne clemensii Ames & C.Schweinf. in O.Ames.
Coelogyne clemensii var. angustifolia Carr
Coelogyne clemensii var. clemensii
Coelogyne clemensii var. longiscapa Ames & C.Schweinf. in O.Ames
Coelogyne compressicaulis Ames & C.Schweinf. in O.Ames
Coelogyne concinna Ridl.
Coelogyne confusa Ames.
Coelogyne contractipetala J.J.Sm.
Coelogyne corymbosa Lindl.
Coelogyne crassiloba J.J.Sm.
Coelogyne craticulilabris Carr
Coelogyne cristata Lindl.
Coelogyne cumingii Lindl.
Coelogyne cuprea H.Wendl. & Kraenzl.
Coelogyne cuprea var. cuprea
Coelogyne cuprea var. planiscapa J.J.Wood & C.L.Chan
Coelogyne dichroantha Gagnep
Coelogyne distans J.J.Sm.
Coelogyne dulitensis Carr.
Coelogyne eberhardtii Gagnep
Coelogyne ecarinata C.Schweinf.
Coelogyne echinolabium de Vogel
Coelogyne elmeri Ames.
Coelogyne endertii J.J.Sm.
Coelogyne exalata Ridl.
Coelogyne filipeda Gagnep.
Coelogyne fimbriata Lindl.
Coelogyne flaccida Lindl.
Coelogyne flexuosa Rolfe.
Coelogyne foerstermannii Rchb.f..
Coelogyne formosa Schltr.
Coelogyne fragrans Schltr.
Coelogyne fuerstenbergiana Schltr.
Coelogyne fuscescens Lindl.
Coelogyne fuscescens var. brunnea (Lindl.) Lindl..
Coelogyne fuscescens var. fuscescens
Coelogyne fuscescens var. integrilabia Pfitzer in H.G.A.Engler (ed.).