The Oncidium Section PLANIFOLIA

This is one of the larger Sections. A number of the plants are grown locally, either as the species themselves, or in hybrids involving these species

These plants are distinguished by their conspicuous pseudobulbs. The flowers have prominent bracts, often small and membranous, as long as, or sometimes shorter than, the stalk of the individual flowers. The petals and sepals are moire or less similar, with the lateral sepals free, shorter than the lip. The disc of the lip has an uneven number of small conical projections without accessory protuberances. The rostellum is short. 2

THE SPECIES

Garay and Stacy 2 list 32 species in this Section: acrochordonia, advena, amabile, ansiferum, baueri, bracteatum, cardiostigma, celsissimum, costaricense, cruciferum, ensatum, fasciferum, henrici-gustavi, incurvum, liebmanii , lineoligerum, ornithopodium, panamense, parvif7orum, pelidgramma, pentecostale, pergameneum, picturatum, platyglossum, schmidtianum, sellowii, sphacelatum, stenotis, tenuipes, turialbae, wentworthianum, and wydleri.

Three species only will be discussed in detail:

Onc. baueri has clustered, somewhat compressed pseudobulbs which are somewhat strongly ridged, 75 to 175 mm long, to 40 mm wide, often yellowish in colouration. They bear 1 to 3 leaves, with leaf bracts at the base of the pseudobulbs, which are rather leathery, 300 to 1,500 mm long, and 25 to 65 mm broad. The inflorescence is about 1.6 to 3 metres long, abundantly branched towards the base, the branches gradually shortening upwards, the lower ones mostly 7 to 10 flowered. The whole inflorescence is rather strongly pendulous due to the weight of the flowers. The individual flowers are up to 25 mm in diameter, rather waxy textured and long lived, yellow or yellowish-green spotted or irregularly barred with brown or reddish brown, the lip yellow having a reddish-brown claw and white crest. Mostly spring flowering, it is native of Puerto Rica, Virgin Islands, Martinique, to Brazil, and Peru.1 It has been cultivated since 1840. 6 Because of problems in the original description 6 of Onc. altissimum, that name is sometimes applied to this species.


Onc. incurvum is a very pretty and distinct orchid flowering during the autumn and winter, but sometimes also in the summer, lasting a long time in beauty. It has an erect scape 600 mm high, bearing a racemose panicle of elegant sweet scented flowers.7 It produces oval compressed pseudobulbs, ribbed, on their flattened sides, 75 to 100 mm long. There are 2-3 rather long (450 mm) thin leaves. Hawkes states the inflorescence can be 1 to 1.6 metres long, bearing 25 mm fragrant pink to rose pink flowers, spotted and blotched with white, with a vivid yellow lip crest.1 It has been in cultivation in Europe since 1839.6 Williams,7 describes a plant "several feet in diameter, stated to have consisted of 40 spikes, containing 12,000 flowers" exhibited in Edinburgh UK in 1893. What a magnificent sight it must have been!


Oncidium incurvum

Onc. sphacelatum has been cultivated since 1840,6 and is a good free growing, free flowering species, having flowers which last 3 to 4 weeks in beauty.7 The pseudobulbs of this species vary from being clustered together to vaguely distant on a very robust rhizome. They are usually yellowish in colour, almost oblong, compressed with sharp edges, 100 to 175 mm high, 50 to 75 mm wide. There are 2 to 3 rather rigid leaves to 600 mm long. The inflorescence can be 2 metres long, very branched, the branches short and many-flowered. The flowers, when in bud are very characteristically formed with the tips of the petals and sepals bent back like horns. When fully expanded, the flowers are about 25 mm across, quite variable, the petals and sepals usually dark chestnut brown for basal two thirds, somewhat barred yellow on apical third, with yellow margins. The lip is golden yellow with red-brown area in front of the crest. It flowers in the spring to summer period.

Moir 8 considers wydleri, stenotis, ensatum and panamense are desirable and useful species for use in the breeding of large flowered intergeneric hybrids within the oncidiinae.

Plants in this Section appear to be adaptable with regard to their temperature requirements. One. incurvum is a cool growing species, although may respond to some heat. Most of the other species would appear to appreciate intermediate conditions. Carpenter 31 notes that when sphacelatum is used, it imparts certain warmth tolerance to odontoglossum intergeneric hybrids. He also reports incurvum does not impart this characteristic, this perhaps giving us a clue to the temperature requirements of these plants. Incidentally, he notes that in hybrids, sphacelatum is dominant for good spike branching and many flowers.

These plants do not go through the same dormant period required for many oncidiums. They wills as a consequence require watering the whole year, although this would be naturally reduced over the colder winter months. Remember to maintain bright growing conditions with plenty of air movement.

Remember, growing orchids is all about enjoying your plants
and sharing your growing success with friends and family.

Good luck and good growing.

   
   


 


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