ON FROPAaATION BY CUTTINGS. 



249 



ture of from 60° to 65" Fahr., in which the snow melted, I was not deceived 

 in my expectations ; some acacias, such as A. subcoerulea and A. Cunning- 

 hami, and several mammillarias, such as M. uncinata, germinated in the 

 course of two days. These seeds not only germinated well, but in rapidity 

 surpassed my expectations ; and I even succeeded in raising crotalaria pur- 

 purea in this manner, which I had never been able to do before by any 

 other method. When the snow had melted on the latter, I did not cover 

 the seed with a little sandy earth as I had done with the others, but waited 

 till the germ had fau-ly made its appearance, when I put the sand on ; and, 

 from the success of both, I consider the practice is established as generally 

 useful. When newly fallen snow is not to be had, that which is frozen in 

 ice-cellars, and easily preserved till the month of Jnne, will do equally well." 

 (Gard. Mag. for ISil, p. .303.) 



572, The discoveries daily making in chemical science^ promise to throw 

 much light on the germination of seeds; but as they do not seem to be 

 matured, and as much is expected from Liebig's edition of Turners 

 Chemistry^ not yet published, we have deferred giving an epitome of the 

 new doctrines on the subject of germination, till the preparation of our 

 Appendix. 



§ 2. — On Propagation hy Cuttings. 

 578. A cutting is a portion of a shoot containing either leaf-buds, or leaves 

 in the axils of which buds may be produced. It must at least be of suffi- 

 cient length to have two buds or two joints — one at the lower extremity to 

 produce roots, and another at the upper end to produce a shoot. A portion 

 of a stem with only one bud is not considered a cutting, but is techni- 

 cally an eye or joint. Though propagation by cuttings is the most 

 general of any of the artificial modes, yet it is not applicable to stem- 

 less plants, such as the Primula family, nor to the greater number of 

 monocotyledons, which are chiefly bulbous plants, without leafy stems. It 

 is applicable, however, to all woody plants, and to all herbaceous plants 

 which send up stems bearing leaves ; and it is the principal mode of propa- 

 gation employed with woody plants kept in pots under glass. It is almost 

 unnecessary to state that the cause of success is to be found in the analogy 

 between a cutting and a seed ; the bud being the embryo plant, and the 

 alburnum of the cutting containing the nutriment which is to support the 

 development of the bud, till it has formed roots sufficient to absorb nutri- 

 ment from the soil. The roots formed by the cuttings are protruded from 

 the section at its lower extremity, and are, in fact, a continuation of the 

 albumous process, which, had the cutting not been separated from the plant^ 

 would have been employed in adding to its young w^ood and inner bark. 

 Every cutting must either contain a stock of alimentary matter in its albur- 

 num, as in the case of cuttings of ripened wood without leaves, or it must 

 contain healthy leaves, capable of elaborating alimentary matter from the 

 moisture absorbed from the soil joined to the alburnous matter already in the 

 cutting. All cuttings may be divided into two kinds : those made and planted 

 when the plant is without its leaves, as in the case of the common gooseberry 

 or the willow ; and those made of shoots with the leaves on, as in the case of 

 all evergreens and of many greenhouse plants, such as the geranium, the 

 fuchsia, heaths, &:c. In both cases the cutting, after being planted, is excited 

 by heat, and supported by the moisture absorbed from the soil. In the case of 

 the leafless cutting the buds are swelled, and in proportion as they develop 



