Robin has been growing orchids for a long time now, and like many others started with a Phalaenopsis and some Pleiones. When looking for something else and different, she was directed to the Norfolk grower Alex Mellor. As it happened Alex was on the point of retiring, and selling up. Robin bought several mixed plants, one of which was a Coelogyne, and her interest in the genera has grown ever since. She still has that original plant some 20 years later – which is now a specimen. Around 10 years ago, Sam Tsui had a range of Coelogynes available, and several of these were added to the collection. The plants can be quite small as well as some that can become very large and heavy. They aren’t suitable for the windowsill.
The genus comes from Asia, from the Himalayas through Burma, Thailand, Borneo, and into the north of Australia. Some of the species are endemic to their own islands, but many are well spread (common). Borneo has 65 species, and Sumatra has 34.
They were first described by Lindley in the 19th century with 5 sections, and revised by Dressler in 1981, who classified them into 22 sections, which is still the accepted number. Originally there were around 400 species, but many have been synonyms, and the true number is currently just over 220. The species type is cristata, of which there are 5 variants. The name Coelogyne can be pronounced many ways depending on where you want to put the accent, but the name comes from Koilos meaning hollow cavity (deeply excavated stigma) and gyne meaning female. As the plants come from a wide range of habitat they grow between 21-32C at sea level to 1000m with 3-9 months monsoon, and also up to 1800m where it is more cool, and up to 3700m in relatively dry forests with few trees. As a result, there are species in all of the temperature group ranges. The smaller flowering ones tend to grow at higher elevations.
They have 4 methods of producing flowers – which is unusual in a single genus. These can be from the base of the mature growth (Heteranthous), top of the mature growth between the terminal leaves, on a terminal rhizome node (Proteranthous), or produced as the leaves start to grow (immature growth, Synanthous)
The main reason for such a high number of sections is from flowering in these different ways, as well as the climatic range etc. It isn’t possible to go over all of the species, so Robin covered 1 or 2 species from a section where relevant, although some sections are quite obscure and not commercially grown – in which case they are missed out.
Section 1 – Elatae. Contains barbata, which has large flowers that start to develop in February but don’t actually open until November. These are white with a hairy trumpet lip that is brown inside, and will last 6 weeks on up to 20 sequentially produced flowers. elata (syn. stricta) is a large plant with a creeping rhizome, and modest white flowers with yellow lip marking.
2 – Proliferae. This has 6 species, with prolifera and longipes most notable.
3 – Fuliginosa. These are tiny scramblers, very floriferous, with hard texture and hairy lips. Flowers are produced sequentially. fimbriata is typical, and loves a daily misting. ovalis is a spindly climbing plant with small waxy yellowish flowers, with narrow petals.
4 – Micranthae. micrantha comes from hill forests in Burma, generally considered difficult to cultivate, so rarely seen.
5 – Bractypterae. Generally has reddish flowers, but parishii is a pale green form that flowers from the top of the bulb, often after the leaves have been discarded.
6 – Speciosa. This is a nice group that are good do’ers, with speciosa having pendant yellow/brown flowers with a brown lip. incarnata has green petals, and usitana is a new species (2001) with large white flowers and a hooded red lip that are too heavy for the spike to hold. xyrekes has dark leaves and reddish flowers. Natural hybrids are often seen within this section.
7 – Bicellae. bicamerata is typical with insipid white flowers.
8 – Monofiliforme. monilirachis is the type with dark leaves and red flowers.
9 – Longifoliae. Contains 28 species of sequential flowering plants that last a long time. prasina is typical, with various colour forms..
10 – Cyathogyne. These are multiflorals with tall spikes and lots of flowers.
11 – Verucchosa. This group have pendant flowers that generally smell of mould. asperata has brownish flowers, whilst pandurata is mainly yellow with a black lip. mayeriana is a green form with a whitish lip and black mottling.
12 – Tormentosae. tomentosa (syn. massangeana) is a well known species with a floppy spike and brownish flowers. rochusennii is another with pale brown hanging flowers. Flowers in this section can be produced all year around (uncoordinated), are perfumed and can last up to 6 weeks.
13 – Hologyne. miniata is a climber with small orange flowers and needs a daily misting. prasina has pale yellow flowers
14 – rigidformes. Rarely seen spring flowering group that is hard to cultivate.
15 – Veithchiae. This group come from New Guinea, and typically have small pretty white flowers.
16 – Ptychosae. flexuosa is described as a modest, insipid flowering plant.
17 – Lawrenceanae. This section contains lawrenceanum whichis a large plant with yellow – brown flowers reaching 4” across. eberhardtii is nicely coloured.
18 – Coelogyne. This contains the species type cristata which has crested keels. This is probably the most widespread species and has the most varieties. It rapidly forms heavy specimen plants with round bulbs on short rhizomes. Var. citrana/lemoniana is perfumed, and var. hololeuca/f. alba is a pure white form. mooreana is a large plant with long racemes of full white flowers with a yellow throat. This species likes to be pot bound to flower, and doesn’t like being repotted – although 2 weeks after flowering is about the best. High light and warmer conditions are preferred.
19 – Fuscantes. Contains the never seen assamica and nitida (syn. ochracea). nitida is a well known small perfumed plant – or does it stink?
20 – Ocellatae. Contains punctula & corymbosa, small plants with long spikes of small white flowers with well defined yellow marks on the lip.
21 – Lentiginosae. Contains lentiginosa a pale freckled flower. chloroptera is a yellow flowered species with a winged column. mossiae is a small flowered species with very pale brown flowers. marmorata has a hanging spike with pale green flowers with a distinctive white lip mottled with brown.
22 – Flaccidae. flaccida (syn. lactea) has a hanging spike with pale yellow to peach coloured small flowers. trinervis is a large spreading plant noted by having 3 spines under the leaves. viscosa (syn. graminifolia) has arching spikes of open starry flowers from white to pale pink, and has very delicate leaves.
New species are still turning up, and there are still a few to be described. There are some natural hybrids, and a small number of registered man made hybrids. Notable amongst these are Unchained Melody (cristata x flaccida), Memoria W. Micholitz (lawrenceana x mooreana), Intermedia (cristata x tomentosa), and last but by no means least Burfordiense (asperata x pandurata) a huge plant with graceful arching spikes of pale green flowers.
Finally, repotting is best done within a 2 week window around a fortnight after the flowers have died back. Repotting at other times tends to upset the plant and a degree of sulking will inevitably result. A good round of applause followed this introduction to the genus. Not all the species were covered – either ‘common’ or rare so if you would like to know more about them a good book on the genus is available (by Dudley Clayton).