Mar.] 



GREEN-HOUSE AND CONSERVATORY. 



1039 



should be preferred. The proper time for taking cuttings from 

 the mother-plant is when the sap is in full motion, in order 

 that, in returning by the bark, it may form a callous or 

 protruding ring of granular substance between the bark and 

 wood, whence the roots proceed. As this callous, or ring of 

 spongy matter, is generally best formed in ripened wood, the 

 cutting, when taken from the mother-plant, should contain a 

 part of the former year, or in plants which grow twice a-year, 

 of the wood of the former growth, or in the case of plants 

 that are continually growing as most evergreen exotics, such 

 wood as has begun to ripen or assume a brownish colour. 

 This is the true principle of the choice of cuttings as to time ; 

 but there are many sorts of trees, as willow, elder, &c., the 

 cuttings of which will grow almost at any season, and even if 

 removed from the mother-plant in winter, when the sap is com- 

 paratively at rest. In these, and other trees, the principle 

 of life seems so strong and so universally diffused over the 

 vegetable, that very little care is requisite for tlieir propagation. 

 Cuttings from herbaceous plants are chiefly chosen from the 

 low growths which do not indicate a tendency to blossom ; but 

 they will also succeed in many cases when taken from the 

 flower-stems, and some rare sorts are so propagated." Tlie 

 leaves of some plants, especially such as are succulent, will 

 form plants, such as Bryophyllitm, Iloija^ See. ; and the late 

 Professor Thouin observes, that the same may be stated of 

 certain flowers and fruits. 



In the case of plants which do not readily protrude roots 

 by cuttings, artificial means are sometimes made use of 

 to induce this disposition in them ; several curious notices 

 have appeared in the Transactions of the Hort. Soc. upon this 

 subject. Ringing the cutting, that is, if a piece of the bavk 

 in form of a ring be removed off' the cutting previously to its 

 separation from the mother plant, a callous will be formed, 

 which will readily emit roots when taken off* and planted in 

 the ground; and it has been conjectured that a li^ati re 

 would operate in a similar manner, though not so effectually, 

 if made to encircle the shoot destined for a cutting, and should 

 be taken off" when an accumulation of sap has apparently been 

 produced. In either case, the cutting should be amputated 



