three holes to correspond being cut into the scion.  When fixed, the top should be securely fastened by tying it to the pot, or by means of stakes.  For this last operation, a little patience and care are necessary to make the stocks and scions fit properly; but if the rules that apply to grafting are properly followed, there will be little fear of the operation failing.  In the accompanying illustrations, we have a small Mamillaria stem grafted on to the apex of the tall quadrangular-stemmed, night-flowering Cereus (Fig. 7), and also a cylindrical-stemmed Opuntia worked on a branch of the flat, battledore-like Indian Fig (Fig. 8.)

[Illustration:  Fig. 7.—­Graft of Mamillaria RECURVA on cereus nycticalus.]

[Illustration:  Fig. 8.—­Graft of opuntia DECIPIENS on O. Ficus-indica.]

In the hands of a skilful cultivator, the different Cactuses may be made to unite with one another almost as easily as clay under the moulder’s hands; whilst even to the amateur, Cactuses afford the easiest of subjects for observing the results of grafting.

CHAPTER V.

THE GENUS EPIPHYLLUM.

(From epi upon, and phyllon, a leaf).

It is now about a century since some of the most beautiful of Cactaceous plants came into cultivation in this country, and amongst them was the plant now known as E. truncatum, but then called Cactus Epiphyllum; the name Cactus being used in a generic sense, and not, as now, merely as a general term for the Natural Order.  Introduced so early, and at once finding great favour as a curious and beautiful flowering plant, E. truncatum has been, and is still, extensively cultivated, and numerous varieties of it have, as a consequence, originated in English gardens.  We do not use the seeds of these plants for their propagation, unless new varieties are desired, when we must begin by fertilising the flowers, and thus obtain seeds, which should be sown and grown on till the plants flower.

Epiphyllums have already “broken” from their original or wild characters, and are, therefore, likely to yield distinct varieties from the first sowing.  In the forests which clothe the slopes of the Organ Mountains, in Brazil, the Epiphyllums are found in great abundance, growing upon the trunks and branches of large trees, and occasionally on the ground or upon rocks, up to an elevation of 6000 ft.  It was here that Gardner, when travelling in South America, found E. truncatum growing in great luxuriance, and along with it the species known as E. Russellianum, which he sent to the Duke of Bedford’s garden, at Woburn, in 1839.  These two species are the only ones now recognised by botanists, all the other cultivated kinds being either varieties of, or crosses raised from, them.  The character by which Epiphyllums are distinguished from other Cactuses, is their flattened, long, slender branches, which are formed of succulent, green, leaf-like branchlets, growing out of the ends of each other, to a length of from 3 ft. to 4 ft.  As in the majority of Cactuses, the stems of Epiphyllum become woody and almost cylindrical with age, the axes of the branchlets swell out, and the edges either disappear or remain attached, like a pair of wings.