PL. 35. ODONTOGLOSSUM ANDERSONIANUM.
ODONTOGLOSSUM ANDERSONIANUM.
[[Plate 35].]
Native of New Grenada.
Epiphytal. Pseudobulbs ligulate-pyriform, costate, two or three inches high. Leaves broadly linear, acute, about a foot long, of a light green colour, two from the top of each pseudobulb, with occasionally another from its base. Scape radical, spreading, more or less drooping, supporting a branching raceme about two feet long. Flowers resembling those of Odontoglossum Alexandræ, but smaller, prettily spotted; sepals ovate-oblong, acute, slightly crispy, creamy white, heavily and irregularly blotched on the lower half with bright chestnut-brown, the attenuated upper half unspotted; petals similar in form and colour, the blotches which are also on the lower half smaller, and more thickly placed; lip from a cuneate base, pandurate, narrow in front, apiculate, distinctly wavy and toothed, creamy white, yellow at the base, with fewer and smaller brown spots; disk deep yellow, with a prominent crest dividing in front into two divergent horns. Column greenish towards the base, brown in front, the wings and anther-case white.
Odontoglossum Andersonianum, Reichenbach fil., in Gardeners’ Chronicle, 1868, 599; Id. 1872, 41; Floral Magazine, 2 ser., t. 45.
The charming Odontoglossum Andersonianum, supposed to be a wild mule between O. Alexandræ (crispum) and O. præstans or O. gloriosum, is one of the many prettily spotted Odontoglots which have been introduced into our collections during the past few years, and among which new varieties are continually appearing. One of the best forms of this plant which has come under our notice is that represented in the accompanying plate, prepared from a very beautiful specimen which bloomed last year among many other fine Odontoglots, well cultivated in the collection of Messrs. William Thomson & Sons, of Clovenfords near Galashiels.
The Odontoglossum Andersonianum is a compact-growing plant, with pyriform pseudobulbs two to three inches high, pale green leaves, and gracefully drooping branched flower-spikes about two feet in length. The sepals and petals are at first creamy white, spotted with purplish brown, the lip being also white, but less heavily spotted. The plant is of free-blooming habit, the flowers continuing fresh and perfect for a period of five or six weeks. It is exceedingly difficult to recognize this form until it produces its blossoms, as its growth is remarkably similar to that of O. Alexandræ. Indeed there are many forms and varieties of this particular group which it is impossible to recognize until their flowers are seen; and, though cultivators may sometimes feel assured of the identity of individual plants, the production of flowers not unfrequently proves them to be mistaken.
Odontoglossum Andersonianum requires the same treatment as O. Alexandræ and other cool Orchids, also the same amount of water. The plants must have good fibrous peat to grow in, and plenty of drainage, as they need to be freely supplied with water all the year round, and this, if allowed to become stagnant, would prove very injurious to them. The material in which they are grown must also be clean and sweet; and though they must never be over-potted, sufficient space should be allowed for their roots. We have sometimes seen Odontoglots in pots far too large for them, and though this may tend to make the plants more important-looking, yet it will eventually spoil them, as the larger amount of soil becomes soddened with water, and this produces rotting of the roots.
Raised Blinds for Orchid Houses.—During the summer months we have found Raised Blinds very beneficial to the growth of Orchids, especially to those requiring cool-house culture. When the hot summer’s sun is shining upon the glass, it is very difficult, where Raised Blinds are not employed, to keep the temperature sufficiently low. The glass roof of the structure upon which the sun is shining becomes very hot, even when shaded with ordinary blinds; but if Raised Blinds are used a current of air is allowed to pass over the entire surface of the roof, and the glass is kept comparatively cool. The effect of this is to decrease very appreciably the internal temperature of the house; and the moisture, which would otherwise be dried up by the burning heat of the sun, produces a nice humid genial atmosphere in which Orchids delight. Having thus far referred to the advantages to be derived from the use of this method of shading, we may now explain briefly the mode of construction. Supposing that the house to be furnished with Raised Blinds is an ordinary span-roofed structure, it is necessary in the first place to provide a second ridge elevated about six inches above the top of the existing one. This should not consist of a solid plank, but of a strip of timber sufficiently strong to bear the weight and strain of the blinds and roller, and should be supported on blocks of wood placed at intervals in order to allow the current of air from below to find an outlet, which would not be the case if a solid ridge-board were adopted. Having arranged for the ridge, the next thing is to provide supports for the rollers; either wood or iron may be used for this purpose, but we have found iron to be the lightest looking and the most durable. Where the length of the rafters does not exceed say eight feet, half-inch rod iron will be found to be strong enough, and this should be cut into proper lengths, with the lower end turned up in a semi-circular form, so as to catch the roller when it descends, and prevent it from running off the supports. These supporting rods should be fixed to the bars or rafters of the house, about six inches above the woodwork, by being welded to vertical iron stays, which latter should be flattened out at the base, and provided with holes so that they can be screwed to the rafters or bars of the roof. In this way a strong support for the blinds to roll upon will be formed; the blinds themselves can be attached to the elevated ridge in the ordinary way, and the gearing usually employed for the purpose will be found to answer well for pulling them up or down. Many Orchid growers have already adopted these Raised Blinds with very beneficial results.—B. S. W.