198 ORCHIDS. 
dipping in a mixture of tobacco and soft soap, will destroy 
these pests. Snails are also very fond of the young growths 
of these plants; they must be kept under by setting 
traps, as already advised (page 12), or by examining the 
plants at night, when the snails come out to feed. 
Pruning has been recommended by several successful 
growers of Dendrobiums. By this is meant the removal 
of all the old pseudo-bulbs, leaving only those that have not 
yet flowered. Some leave all the pseudo-bulbs that are 
three years old and under. The latter plan is certainly the 
safer, and it may be adopted for most of the free-growing 
kinds with advantage. At the same time, it is well to 
bear in mind that some of the finest Dendrobiums ever 
seen have been grown without the removal of a single 
pseudo-bulb from the commencement. 
Propagation.—Those kinds which have jointed, bamboo- 
like pseudo-bulbs are readily multiplied by removing the 
ripe pseudo-bulbs from an old plant, cutting them into 
lengths of 6in. or so, and fastening them on to pans or 
baskets of moist sphagnum moss. Under this treatment, 
the pieces soon push eyes, and these, when rooted, may 
be removed and planted separately, leaving the stem till 
it has exhausted itself. Such species as D. bigibbum, 
D. crassinode, D. fimbriatum, D. nobile, D. Phalznopsis, 
and D. Wardianum, are easily propagated in this way. 
D. aggregatum.—A dwarf-growing species, which should 
be fastened upon a bare block of wood, green elm or thorn 
being best; it does not exceed 3in. or qin. in _ height. 
The pseudo-bulbs, each of which bears a solitary leaf, are 
crowded, angular, 2in. long, and deep green. The flowers ~ 
are clear yellow, becoming deeper with age, the lip dark 
yellow in front; they are borne in arching racemes about 
6in. long. This species blossoms during March, April, 
