12 CACTACEOUS SLANTS. 



portions to remain attached. Large specimens in tubs or pots of con- 

 siderable size seldom need repotting, a top-dressing of fresh compost, 

 with occasional supplies of weak lic[uid manure, being amply sufBoient. 



PROPAGATION. 



The majority of the Cacteas are readily increased by cuttings, grafting 

 and by seeds, each of which methods may be briefly described. 



Cuttings. — The species of Cereu?, Opuntia, Ehipsalis, Epiphyllum, 

 and others with cylindrical or slender angular stems, can be increased by 

 means of cuttings of the young growths, which may be taken off in the 

 spring and summer and placed in a sunny position for a few days, until 

 the cut surface has healed, or until a few roots are seen to be forming. 

 They can then be inserted in pots of light sandy soil, and kept quite dry 

 until growth commences, when slight syringing will be beneficial. The 

 temperature of the house in which the plants are grown will be sufficient. 

 The Mamillarias and some species of Eohinocactus and Echinopsis produce 

 a number of offsets from the base of the stems, which may be removed and 

 treated like cuttings, and a, large stock can be soon obtained of many 

 species in this way. 



Grafting. — The principal object of grafting in this family is to place 

 delicate species upon stocks of a stronger character, so that there is less 

 danger of the former suffering from superfluous moisture in the soil, as 

 with some Mamillarias, or to elevate pendulous or drooping plants upon 

 a stem, so that they can be seen to better advantage, as in the case of 

 the Epiphyllums. Some of the slender Cereus seem ta be benefited by 

 being graited on stronger stocks both in their growth and floriferousness, 

 but the latter character is usually not much affected. There is one great 

 obiection to grafted plants, and that is that usually they have an incon- 

 gruous appearance almost approaching to deformity, and on this account 

 many growers do not practise it. The operation is generally performed 

 in early summer when growth is proceeding, and the methods employed 

 are extremely simple. The stock selected is usually a Cereus, such as 

 C. tortuosus, C. macrogonus, or C. peruvianus, according to the habit 

 of the plant from which the scion is to be taken, the second-named 

 being one of the quickest growing of all, or the Pereskia aculeata ; but 

 this is principally reserved for the Epiphyllums. If one of the small 

 globular Mamillarias, Eohinocactus, Echinocereus, or Echinopsis is to be 

 the scion the base should be cut smoothly across, and if the stock is a 

 sufficiently broad stem this can be similarly smoothed and the scion placed 

 level upon it, being secured in its place by matting or string passed over 

 the plant and under the pot, so as to keep the cut surfaces in close contact> 



