e Fig. 5) of the plant is
different from that of the Cereus, and is more like that of a cucumber.
Still, though the form is different, the purpose of the two cotyledons
and the juicy stem in the seedling Opuntia is the same as in the Cereus;
and, as the growing point develops, the cotyledons shrivel up and fall
off, the plant food they contained having passed into that part of the
young seedling which was to be permanent. The seedlings of these two
genera serve as an illustration of the process of germination from seed
of all the Cactuses; and it must be evident that there is much that is
singular and full of interest in raising these plants from seeds. As
soon as the seedlings are large enough to be handled, they may be
planted separately in small pots, using a compost similar to, but
slightly coarser than, that in which the seeds were sown. The soil
should be kept moist till the summer is over; and after that, till the
return of warm sunny weather, it will be found safest to keep the
seedlings on the dry side, a little water only to be given at intervals
of a week, and only when the sun is shining upon the plants.

To obtain seeds from cultivated plants, it is necessary, in order to
insure fertilisation that the top of the stigma (see Fig. 2) should be
dusted over with the dust-like pollen from the anthers. This may be done
by means of a small camel-hair brush, which should be moistened in the
mouth and then pushed among the anthers till covered with pollen, which
may then be gently rubbed on to the stigma. A warm, sunny morning is the
most suitable time for this operation, as fertilisation takes place much
more readily under the influence of bright sunshine than at any other
time. Some of the kinds have their floral organs so arranged as to be
capable of self-fertilisation; still, it is always as well to give them
some assistance. The night-flowering species must, of course, be
fertilised either at night or very early in the morning. By using the
pollen from one kind for dusting on to the stigma of another, hybrids
may be obtained, and it is owing to the readiness with which the plants
of this family cross with each other, that so many hybrids and forms of
the genera Epiphyllum and Phyllocactus have been raised. It would be
useless to attempt such a cross as Epiphyllum with Cereus giganteus,
because of their widely different natures; but such crosses as
Epiphyllum with Phyllocactus, and Cereus flagelliformis with C.