The Oncidium Section CUCULLATA

A Section containing seven species producing colourful and attractive flowers 4 being andigenum, olivaceum, phalaenopsis, nubigenum, storkii, tripterygium and warscewiczeii. These plants have conspicuous leaf bearing pseudobulbs. The sepals and petals are stalkless, spreading, the lateral sepals joined to a bidentate tip as long or shorter than the lip. The disc of the lip has an uneven number of tubercules and the rostellum is short.

Since the original Garay and Stacy review, J.E. Stacy has completed a detailed study 4 of this Section. The Cucullata Section has been plagued with confusion and misunderstandings since the very early days of European importation, and this more recent analysis makes some order out of this Section. As the result of the wore detailed studies, 19 species are now considered to be valid - aequioctiale, alticola, andigenum, azuayense, chimborazoense, cucullatum, (and varieties cucullatum, dolabratum, macrochilum), dayanum, erosilabium, kennedyi, mimeticum, nubigenum, olivaceum (and var. olivaceum, giganteum), phalaenopsis, rhodostictum, sanguinolentum, spathulatum, targuiense, tripterygium, and tunguraguense. Stacy's article 4 should be referred to for a description of these species, and for an intersectional key to their identification.

One. olivaceum is described by Williams under the synonym cucullatum 2 as being "a small flowered species, but a very beautiful one." It is a dwarf growing plant bearing charming flowers in nodding racemes, rarely in panicles. The flowers are produced in the spring, and last a long time in perfection. There are many varieties, differing much in colour.

This species is highly variable in all parts. The pseudobulbs are clustered, oval, compressed, rather dull green in colour, 30-75 mm long. There are 1-2 leaves, sharply pointed, folded at their bases, 150-200 mm long. The inflorescence is slender, erect or nodding, to about 600 mm tall, usually 8-12 flowered. The flowers are some 35 mm long, variable in colour, the sepals and petals typically dark chestnut brown, sometimes greenish or olive-green, rarely with a narrow yellow margin. The lip is light rose purple, more or less spotted with purple crimson. Summer to autumn flowering, it is native of Colombia, Ecuador, usually at high elevations,1 normally up to 2650 metres above sea level' 7 but some forms are found up to 4,000 metres above sea level.7


Oncidium olivaceum

The natural variability of this species has created identification problems. The Dictionary of Gardenin6 lists eight varieties of this species, two of which (phalaenopsis and nubigenum) are shown as separate species by Garay and Stacy. 2 Nubigenum is distinguished from olivaceum by being a smaller plant,7 having a white lip with violet blotches in from the crest.6 Phalaenopsis has creamy white sepals and petals, the former mottled, the latter barred red-violet, its lip broad, creamy white spotted violet-crimson.6

CULTURE

These plants require conditions similar to that given to odontoglossums, as they are high elevation plants. Temperature extremes should be kept to a minimum. As they are naturally subjected to winds containing constant misty precipitation such conditions should be duplicated in our culture as far as is possible. Stevens, 32 in a recent article, notes that One. olivaceum (cucullatum) grows in the lower montane regions in wet forests where most of the rainfall is in the April to October period. Some of these plants can be difficult to maintain in glasshouse conditions, Stevens believing this to be due to the very free flowering nature of these plants. He says they throw flower spikes with new growths, and as these spikes are very large and large flowered he nipped out the flowers from his plants until such time as they had built up sufficient strength and strong back growths. This treatment seemed to have succeeded, as they now flower freely and seem so much stronger and healthier. The lower montane region mentioned by that author exists at an altitude of between 1,900 and 3,000 metres above sea level, subjected to mean temperatures of 10- 18 0C.

Remember, growing orchids is all about enjoying your plants
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Good luck and good growing.

   
   


 


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 Site established 9th May 1998
Oncidium series first uploaded 20 October 1999