ding, which may be
tacked on in spring and left until autumn; or, preferably, so fitted
that it can be rolled up when it is not required.

SELECTION OF SUBJECTS FOR HYBRIDISING

The best varieties procurable should always be selected for hybridising,
it having been proved that crosses originally made with indifferent
varieties are much finer when raised again from more carefully selected
varieties.

There seems to be no certain limit to the possibility of crossing; even
the most dissimilar genera may be crossed with some probability of
getting a successful result.

POTTING MATERIAL FOR HYBRID ORCHIDS

From the time the little plants are well established in single pots, the
same potting material used for all of their kind may be employed, the
plants in the earlier stage having the potting material in a finer
condition than that provided for the larger plants as they approach the
flowering stage.

As with other important operations, in Orchid potting and in the
material used the practice varies considerably, even in the best
collections, and this points to the fact that if the accommodation is
good, the houses properly heated, and other details of culture carefully
carried out, the exact composition of the potting material is of minor
importance. For Cattleya and Laelia hybrids and a large number of
epiphytes grown with them the compost is made by tearing up the
materials with the hand, or in some other way which will not break the
fibres very much. Osmunda fibre forms one-half to two-thirds of the
compost, the other third being made up of good Sphagnum-moss and Oak
leaves or other decayed, dryish leaves. We do not recommend leaf-soil or
leaf-mould, which was formerly strongly advocated, especially by
Continental growers, who used it with disastrous results. The most that
is done now is to mix a proportion of it with other potting material for
Lycastes, Calanthes, Phaius, and similar strong-growing terrestrial
Orchids.

For mixing with the compost for hybrid Orchids, some use crushed crocks,
sand, charcoal, and a small proportion of each or either may be employed
safely, although there is no real need for such materials.

Polypodium fibre may also be substituted for Osmunda fibre, or a
proportion of each may be used. Orchid peat fibre, which used to be the
chief potting material for Orchids, is still perhaps as good as any of
the other fibres, provided a really good quality can be obtained, a
matter which h