Home › O › Oncidium (From onkos a tumour referring)

Oncidium (From onkos a tumour referring)

(from onkos, a tumour; referring to the warty crest on the base of the labellum). ORD. Orchideae. A large genus of epiphytal Orchids, inhabiting tropical America and the West Indies. Over 250 species have been described, and a large proportion of these have been, or are still, cultivated in English collections; whilst additions are being frequently made, both to the number of species and to those in cultivation. The flowers show remarkable variety, both as regards size, form, and colour; in the latter, yellow predominates. They are borne either in long, flexuose racemes, or in dense, clustering spikes, a few being distinguished by one-flowered scapes; peduncles from the base of the matured pseudo-bulbs generally accompany the new growth. Leaves variable in size and form, often thick and leathery, sometimes thin and papery. Pseudo-bulbs generally compressed laterally, ovate-oblong, rotundate, or cylindrical; in a few species almost or entirely suppressed. From an altitude of 12,000ft. or 14,000ft., where snow and frost are frequent, and where, at all times, the atmosphere is cool, and laden with moisture, several of our popular garden Oncidiums are obtained; and from this extreme elevation, down to the hot, moist valleys of the most tropical parts of America, the species are found luxuriating under very varied conditions. Some of them grow well only when kept in bright sunlight and a tropical temperature, whilst others require shade, with a medium amount of heat and moisture; others, again, thrive only when kept quite cool and moist, and placed out of the reach of direct sunshine.

The wide range of distribution over which the Oncidiums extend, and the often wide difference in the conditions under which they grow in a state of nature, suggest that, for their cultivation here, houses of both tropical and intermediate, as well as cool, temperatures are necessary, if a representative collection is to be grown. Taking, first, the tropical species, of which O. Cavendishianum, O. Lanceanum, and O. Papilio may be cited as examples, it will be found that, to grow these well, a moist stove is necessary, and that, during the season when growth is most vigorous, the conditions requisite in the case of East Indian Orchids must be maintained for these tropical