A remarkable and varied group of Orchids which are found chiefly from Ceylon to Java, but also in Central and South America, particularly in Brazil: they grow wild on trees. None of the American kinds, and only a few of those from eastern Asia, are worth cultivating, as the flowers of many are insignificant. The name Bulbophyllum is derived from the Greek bulbos, a bulb, and phyllon, a leaf. These plants belong to the family Orchidaceae. (The Orchids treated in this book under the name Megaclinium are by some botanists included in Bulbophyllum.)
Although these Orchids vary greatly in appearance, the pseudobulbs are generally set at intervals on a creeping rhizome and usually each pseudobulb has only one leaf. The flowers are borne singly, or several together, on arching or erect spikes.
Hothouse Orchids. In winter a night temperature of 60 degrees is high enough, but the day temperature should rise 5-10 degrees, and in summer an endeavor should be made to ensure a tropical atmosphere, with a night temperature of 65-70 degrees or higher.
Free drainage is essential, so that even the largest kinds should be grown in pans, rather than in pots. The smaller kinds are placed in pans suspended about 18 in. from the roof glass. Shading must be provided in bright weather.
Repotting should be carried out in spring and early summer when fresh growth begins. Some kinds have creeping rhizomes which eventually grow outside and encircle the pans; those need not be repotted for 3 or 4 years provided the surface compost is renewed annually. In winter these Orchids need far less water than in summer, though the compost of the evergreen kinds must not be allowed to get really dry. A suitable compost consists of cut osmunda fiber. These Orchids also grow satisfactorily in Fir bark.
Propagation is effected by division of the plants, the rhizome being severed when the plant is repotted and the severed pieces, each with several bulbs, are placed in separate flower pans.
The Chief Kinds. The following are the best kinds in the different sections. B. Lobbii, from Burma, and its large-flowered variety, Colossus, have erect stems bearing single flowers 2-4 in. across, buff-yellow marked with purplish-red in summer and autumn. The sepals of B. Dearei, another summer-flowering kind, are streaked and suffused with purple. B. Dearei is a native of Borneo and the Philippines.
Giant Orchids. B. Fletcherianum is a New Guinea kind which bears large purplish flowers in clusters. B. marcobulbon, from New Guinea, is similar in growth but has flowers with shorter, broader segments on short spikes. Both of these bloom at varying periods and the flowers of both are evil-smelling. B. grandiflorum, from New Guinea, is remarkable for the size of the dorsal sepal which forms a hood over the minute petals and lip; both dorsal and lower sepals are olive-green with greenish-white spots—almost snakelike in color; autumn and early winter are the principal flowering seasons. B. leopardinum bears yellow and crimson flowers in summer.