The Oncidium Section Rostrata
This Section contains some 27 species.2 Most are unknown in local collections, although two, cheirophorum and ornithorhynchum, are frequently seen. Both these plants are compact growers and put on an attractive and colourful display. The plants are distinguished by their conspicuous pseudobulbs, which may be either close together or clustered. The flowers have their sepals and petals generally spreading, only rarely bent back. The column is smooth, curved in an "S" shape, bearing an elongate proboscis like rostellum. The type species for this Section is the popular ornithorhynchum.2 Because of their compact size and generally free flowering characteristics, the available forms make ideal additions to any collection.
Garay and Stacy 2 include the following species in this Section: alcicorne, angustisepalum, braunii, cheirophorum, chrysornis, cristatellum, dactyliferum, deltoideum, elephantotis, examinans, hapalotyle, hartwegii, hebraicum, lancifolium, luteum, magdalenae, melanops, miserrimum, ornithorhynchum, ototmeton, pictum, pyramidale, scalerophyllum, tipuloides, trulliferum, xanthocentron and xanthornis.
They are natives of Central and South America (Colombia, Peru and Ecuador).6
The two species locally familiar are:-
The species are listed6 as requiring either cool or intermediate conditions. Williams 7 for cheirophorum, advises odontoglossum conditions. As many come from the higher habitats, subjected to misty rains, a constant supply of water is required although the roots of the plants must never be subjected to stale media conditions. Stevens 32 advises that cheirophorum grows in the lower montane regions in wet forest areas; this confirming a moist growing environment, and that perhaps it may appreciate some heat, although Adnam 33 states that in his experience "some heat may be required, although we have always grown the plant cool". This author also advises ornithorhynchum is a plant easy to grow.
Like most oncidiums, reasonably good light must be provided, especially for cheirophorum, although ornithorhynchum with its "softer" pseudobulbs may appreciate more shade.
The opportunity to acquire members of this Section, and especially the two species described, should not be passed up. They provide an attractive and long lasting display, and have the advantage of not taking up too much space where this is at a premium.
Remember, growing orchids is all
about enjoying your plants
Good luck and good growing.
Site established 9th May 1998
Oncidium series first uploaded 20 October 1999