232 PROP A GA TION B Y LEA VES. 



of the second, but without either callosities or roots. (' Gard. Chron.,' 

 vol. i. p. 782.) 



To induce stems or shoots to produce leaves or growths from which 

 cuttings may be formed, various modes have been adopted, the object 

 of all of which is to stimulate the normal or latent buds. The most 

 common mode with plants in pots or under glass, is by an increase of 

 temperature and atmospheric moisture ; but there are modes which 

 are applicable to all plants whatever, the object of which is to inter- 

 rupt the ascending or descending sap. When the ascending sap is 

 accumulated by art at a joint, and can no longer pass freely onwards, 

 it stimulates the buds which exist there, either normal or adventitious, 

 to develope themselves, and the sap thus escapes organized into the 

 form of leaves or shoots ; while the interruption of the descending 

 sap, more especially under a joint or bud, produces an accumulation 

 or callosity there, which, sooner or later, is organized into roots. To 

 Fig. 181. accumulate the ascending sap at any point, the 



shoot may be bent to one side from that point ; 

 and it may be bent back again from a second 

 point, and if the shoot is long, the operation may 

 be repeated, so as to leave it in a serpentine or 

 zigzag form from every exterior angle in which, 

 as at a, a, in fig. 181, a bud will be developed. 

 Where the shoot cannot conveniently be bent, 

 a notch may be made in it immediately above a 

 bud, so deep as to penetrate the alburnum ; or 

 in the case of more slender shoots, the knife 

 may be merely inserted above the bud, or above 

 several buds, so as to penetrate into the albur- 

 num, and the wound kept open by inserting 

 A shoot lent to cause the wedges in them, as in fig. 179, a. Some days or 

 buds at the angles to wee ks afterwards, according to the nature of the 

 pro plant, a notch or cut may be made under the bud, 



in order to interrupt the sap returned by the leaf, and thus form a cal- 

 losity there for the production of roots. In this way all the buds or 

 joints on a tree or shrub of almost any size maybe prepared ; and if a 

 tree so treated could be covered with moss kept moist, leaving only 

 the buds, or the joints, or points from which buds were expected, 

 exposed to the light ; or if it could be laid down on the surface of 

 soil kept moist, and very slightly covered with soil, or laid down flat 

 on the surface of water, so as just to touch it, a rooted plant, or at 

 least a shoot, would be produced from every bud or joint. In pre- 

 paring buds in this manner, however, it must always be borne in 

 mind, either that the plants require to be kept in a close, moist atmo- 

 sphere, or to have the wounds covered with moss or soil ; for if they 

 are exposed to dry air, they will frequently neither cicatrize, nor emit 

 roots, in consequence of the excessive evaporation which will neces- 

 sarily take place. 



Even the petioles of large leaves may be prepared before they are 

 taken off, by being cut half through near the base, by which means 



