TROPICAL PLANT COLLECTIONS

ON GROWING ORCHIDS FROM SEEDS

by David Moore
The Gardeners' Chronicle 1849

At the present time there are few subjects connected with plant growing on which there is less recorded information than that of growing Orchids from seeds, which appears the more remarkable when the great interest our ablest cultivators have taken in growing this singular tribe is considered, along with their tardiness of increase by division of the plants, and their intrinsic value. I am not aware that there is any case on record of hybridisation being effected among Orchids, though there seems no doubt that such could be accomplished by careful manipulation, an inference I draw from reasoning analogically on experiments made here to get seed.

Observers on this subject will have perceived that many of our indigenous orchids appear to seed freely, whilst comparatively few exotic species among our cultivated collections produce seed, circumstances suggestive of the idea that the latter require artificial assistance, which can be readily afforded, by carefully applying the pollen masses to the viscid face of the column and rostellum. But whether the seed of hardy Orchids be generally imperfect, or the necessary circumstances requisite for vegetation and the subsequent growth of new plants wanting, we certainly do not find crops of young Orchids growing spontaneously in various stages of growth, as occurs with most other endogens, though experience has proved to me that when Orchid seed does vegetate under favourable conditions, a very large number of the myriads of the extremely minute seeds contained in the ovaries are perfect, whether artificially impregnated or not.

Within the last five years, seedlings of the following species have been raised in the Orchid-house at Glasnevin, namely, Epidendrum elongatum and crassifolium, Cattleya Forbesii, and Phaius albus, the seeds of which all vegetate freely.

The manner of sowing the seeds, and treating the young seedlings, has been to allow the fine dust-like seeds to fall from the ovaries as soon as they show symptoms of ripeness, which is readily known by the ovaries bursting open on one side. When this takes place, they are either taken from the plant and shaken gently over the surface of the other Orchid-pots, on the loose material used for growing them in, or on pots prepared for the purpose, after which, constant shade, a steady high temperature, with abundance of moisture, are all requisites which are absolutely necessary to insure success.

In the source of eight or nine days after sowing, the seeds, which at first had the appearance of a fine white powder, begin to assume a darker colour to the naked eye, and if looked at with a Coddrington, or even a simple lens, evident signs of approaching vegetation may be perceived, which increase until the protrusion of the young radicle and cotyledon takes place, which varies from a fortnight to three weeks. From this period of their growth the young plants grow rapidly and the rootlets lay hold of whatever material is supplied to them. If the seeds happen either accidentally or intentionally to be made to vegetate on bare wood, as in some instances has been the case here, the young roots extend themselves in different directions, adhering closely to the bark, and make great progress compared with the growth of the stems, thus affording beautiful examples of the manner in which epiphytical plants fix themselves so firmly on the highest boughs of lofty trees in tropical forests, as well as accounting for the isolated positions they frequently occupy in their natural state.

The principal difficulty to contend with in rearing the young seedlings has been found to consist in their treatment during the first year, particularly the winter months, when they are very liable to perish, if anything approaching to extreme of moisture, drought, cold, or even heat be permitted; though a steady medium of all these requisites is necessary. The second year's growth has been one during which the plants made much progress, and the only two kinds which have been brought to a flowering state have bloomed the third season. These are Epidendrum crassifolium and Phaius albus, the latter being now in flower, exactly three years from the sowing of the seeds.