38 ON THE PROPAGATION OF PLANTS BY CUTTINGS. 



elaborate in any great quantity this gross nourishing matter ; and 

 hence arise stagnation of the juices, and the before-mentioned ap- 

 pearances. The good effect of leaving these cuttings lying, and thus 

 interrupting the growing process, and preventing the superabundant 

 rise of the crude nourishing matter, will be apparent ; and this is the 

 more probable, as it is usual, for the same reason, to put a piece of 

 mould round the cut. 



Cuttings of succulent or fleshy plants must also lie for a time 

 before planting, and on no account in a moist atmosphere, that the 

 surface of the cut may be sufficiently dried. They retain so many 

 watery particles in their cellular tissue that, when this is neglected, 

 the face of the cut soon rots. The species of the families Melocactus, 

 Echinocactus, Mammillaria, Opuntia, Cereus, &c, have an extremely 

 thick bark, and a firm epidermis with very few stomata ; on which ac- 

 count the process of evaporation is so slow that they remain alive for a 

 long time without receiving external nourishment. The dried cuttings 

 of these plants, therefore, are generally planted in dry earth, and set in a 

 bed or house filled with warm air, and are not watered till they have 

 formed roots from the nourishing matter accumulated in themselves. 

 The roots can scarcely ever penetrate the thick bark, and are pro- 

 duced between the wood and the bark. In some of the Opuntia and 

 Cereus species, however, they come out of the bark at the side. The 

 other succulent and fleshy plants which form side roots, such as the 

 Aloe, Haworthia, Sempervivum, Mesembryanthemum, Crassula, 

 Plumieria, and its congeners, as well as all the Cacti, may be watered 

 as soon as they are planted. Lastly, plants with milky juice also 

 require similar treatment, as they are equally liable to damp off. 



As soon as a part of one of these plants is cut off, the milky juice 

 exudes in great quantities, covers the whole surface of the cut, and 

 hardens like caoutchouc, by which the vessels are all stopped up 

 and the ascension of the moisture prevented. Cuttings of Ficus, and 

 the dry roots of Euphorbia, are put in water, where they remain 

 twenty-four hours before they are put in the earth. The same end is 

 also attained when they are put in dry sand immediately after being 

 cut, and afterwards the sand and the milky juice cleared away. Only 

 the succulent and very milky Euphorbias must lie for some time. 



Although it is proved by the above that the cutting receives as 

 much moisture through the face of the cut as it loses in ordinary cir- 



