Oncidium Forbesii, _Hooker_, _Botanical Magazine_, t. 3705; _Lindley_, _Folia Orchidacea_, art. _Oncidium_, No. 60; _Williams_, _Orchid Grower’s Manual_, 5 ed., 254.
The genus _Oncidium_ is a very large one, and there are many species well known in cultivation, but the one we now illustrate belongs to a section in which there are few that are so distinct in colour. The flowers are not so large as in _O. crispum_, of which there are many distinct varieties, differing in size and colour—variations which often depend on the vigour of the plants. The same may be said of _O. Forbesii_, the stronger the bulbs the finer the blossoms. Our sketch was taken from a well-grown plant in the collection of E. Bonny, Esq., Downs Park Road, Hackney, who is forming a choice collection of Orchids.
_Oncidium Forbesii_ is an evergreen species, with pseudobulbs of a greenish brown colour; the foliage is of a dark green, and the flowers are chestnut-brown, with the sepals and petals irregularly margined with bright lemon-yellow. It blooms at different times of the year, and lasts for several weeks in perfection. We find the plants do well in small pans or baskets, and also on blocks of wood. When grown in pans or baskets we have found them grow freely in good fibrous peat, with pieces of charcoal on the top of the peat, as they like to work their roots in among the charcoal, and should have plenty of drainage, and but very little peat earth. When cultivated on blocks they require more water in the growing than in the resting season.
These plants are not long-lived under our artificial treatment. There is something wanted that we do not or cannot supply, and hence it is difficult to keep them for any long period in a thriving condition. They seem, indeed, to wear themselves out by over-flowering or other causes which are very difficult to find out. The same thing happens in the case of some other Orchids. The bulbs of these plants should, if possible, be kept from shrivelling. They often seem inclined to shrivel after they have bloomed freely, and sometimes they lose their roots, especially when they have their flower-spikes left on too long. If the plant is not in a vigorous condition, it should not be allowed to bloom. We find they do best at the coolest end of the Cattleya house, kept as near to the glass as possible, but shaded from the hot sun, with sufficient water to keep them moist during the growing season.