The Oncidium Section CONCOLORIA

This Section is a relatively small one, but contains several desirable specimens for the glasshouse. The plants are generally modest in size, but possess the desirable attribute of producing comparatively large bright and attractive flowers. Garay and Stacy2 distinguish this Section by the plants bearing conspicuous, leaf bearing pseudobulbs, which are clustered together. The flower petals and sepals are spreading or forming an open throat or mouth. The lip arises from a wedge-shaped base, the narrow end at the point of attachment, without lateral lobes. The disc is provided with an even number of parallel keels. The column is rather short, bearing small ear-like appendages, with a short rostellum. Flowers are medium to large in size.

THE SPECIES

10 species are listed by Garay and Stacy,2 brachyandrum, concolor, dastyle, disciferum, endocharis, gracile, hyphaematicum, obovatum, russellianum and speciosum. Only one, concolor, is seen locally.


Onc. concolor was discovered in the Organ Mountains region of coastal Brazil, and was introduced into European cultivation in 1839. Williams 27 describe it as being a very distinct and beautiful species. Hawkes 1 notes it has clustered oval-oblong pseudobulbs 40-50 mm long, becoming strongly ribbed with age. There are two to three bright green rather leathery leaves some 150 mm long. The inflorescence is 6-12 flowered, hanging, to 300 mm long. Individual flowers are about 50 mm long, vivid canary yellow. The lip is clawed, with a spreading blade, roundish to broadly heart shaped. It is early summer flowering. This species is also known as ottonis, (this name properly applies to a species of Cebolletae), and unguiculatum.


Oncidium concolor

Other species are:-

One. brachyandrum is a delicate little species native of South Mexico. It has cinnamon sepals and petals and a yellow lip which is broadly fiddle shaped. pseudobulbs are 25 mm high, two leaved, the leaves 100 mm long. Cultivated since 1871 7

One. dastyle is a dwarf winter to spring flowering Brazilian species having 30-50 mm flowers. The sepals and petals are yellow, blotched red brown. Lateral sepals are joined to the middle. The lip is bright yellow, having a curious black/maroon two lobed crest. Peduncles can be 300 to 450 mm high, sometimes branched. Pseudobulbs are compressed, 30 mm high.7 This species is considered by some authorities to be one parent of gardneri (Crispa Section) with forbesii, where this is considered to be a natural hybrid. In a review by Fowlie of the Section Crispa, he believes gardneri to be a species in its own right.

One. endocharis has about five bright orange flowers, lip strap-like with lozenge shape, notched at its apex, bearing two large crests bearing three teeth at the base. The raceme is slender, appearing in the winter. Cultivated since 1884.7

Onc. gracile, another species from Brazil, has been cultivated since 1837. Its sepals and petals are small, brownish green in colour, with a yellow lip. This is 12 mm long, nearly as wide, bearing a disc with two lamellae. The peduncle is 300-400 mm high, bearing 3-6 flowers. pseudobulbs are roundly ovoid, 20 mm high, bearing two leaves 50-75 mm long. Refer to Synsepala Section for habit notes concerning this species.

One. hyphaematicum bears 40 mm flowers, blood red outside. The sepals and petals are purplish-brown, blotched deeper, tipped yellow. The lip is rich deep yellow, broadly kidney shaped, sharply pointed. It bears a raceme one to one and a half metres long, loosely branching. Summer flowering, it has solitary leaved . pseudobulbs 75-100 mm high. Native of Ecuador, it has been cultivated since 1869.

CULTURE

Quite a number of the species of this Section are native of the Organ Mountains region of Brazil, the foothill monsoonal rainforest habitat. . This region is subject to seasonal climatic variations, and it is appropriate to consider these in our culture. During the winters, temperatures are quite cool, but precipitation is low with little rainfall. Many of the trees are deciduous, so light conditions are bright. During this period there is little if any plant growth. The spring and summer is a period of heavier rainfall. , with the environment subject to frequent misty rainfall conditions. Temperatures will also be much higher. The sun will be much brighter, although some partial shading will be provided by the new leaves growing on the host trees. A distinct feature of the environment is the constant air movement through and around the foliage, and this feature should be duplicated in the glasshouse if the continued health and wellbeing of the plant is to be ensured. Cold damp stagnant growing conditions will lead frequently to rots and disease. Culture can be summarised, cool and dry during the winter, warm and moist during the rest of the year when plant growth is apparent.

The published cultural information indicates that both cool 7 to intermediate to hot 32 conditions are required. This perhaps arises through the differing seasonal variations noted above.


For Onc. concolor, Williams 7 notes this "is a fine subject for growing in baskets in the cool house, where it succeeded best." He also indicates Onc. dastyle should be grown in the cool house, suspended from the roof.

 
 

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