The rain orchid
Many large and colourful wild Dendrobium orchids of the Chiang Mai area bloom in the hot dry season (March-April). The Dendrobium blossom of the rainy season (May-September) tend to be smaller, but there are exceptions. Right now you will find the pink or lavender Dendrobium cumulatum (Orchidaceae) in blossom both downtown and at Dokmai Garden. An English vernacular name is ‘The Crowded-Inflorescence Dendrobium’ which is a direct translation of ‘cumulatum’. Since this is quite an exceptional plant and a nice blotch of colour when most other Dendrobium are green, I think ‘rain orchid’ is a better name. August and September are the rainiest months in Chiang Mai.
It is found from eastern Himalaya all the way down to Borneo, and although I have never seen it in nature, judging from its behaviour at Dokmai Garden it seems adapted to wet environments. Unfortunately the literature does not reveal much of its habitat, and we ask our readers to share knowledge on this matter, so that the Orchid Ark can grow it under perfect conditions.
One striking feature of this Thai orchid species is the unusually long spur-like mentum. ‘Cumulatum’ refers to its tendency to accumulate many flowers on a short stalk.
Text & Photo: Eric Danell