46(5 CONSERVATIVE ORGANS. [LKCT. IX. 



period at which the scales drop, differs in different 

 plants; in some, as the common Lilac for instance, 

 the more succulent inner scales remain attached 

 until the shoot has attained to a considerable 

 length ; whereas in the Lime tree, Tilia Europea, 

 they drop before the leaf is fully expanded. Gems 

 are scarcely ever formed in the axillae of the scales. 



Gems differ in their characters in the same 

 family of plants * 3 and even when found on the 

 same tree; and, as the external form of the gern 

 indicates the nature of its contents., Botanists have 

 arranged them into three species, leaf-gems, flower- 

 gems, and mixed gems. 



1. Leaf-gems, or buds ( Gemmce foliiferce), 

 are long, slender, tapering, and acute, generally 

 containing, besides leaves, the rudiments of a 

 shoot, on which account they are also termed 

 wood buds; and are, in truth, embryon branches^. 



* " Gemmae in eodem genere saepe diversissimae, uti constat 

 " ex genere Rhamiii, ubi Cervispina, Alaternus^ Paliurus, 

 " Frangila, gemmis diversae sunt.'' Phil. Bot. 278. 



f On this fact is founded the process of budding or inocula- 

 tion, which is generally performed in July and August, and is 

 preferred to grafting for such trees as are liable to exude much 

 gum. To perform the operation, a transverse incision is 

 made in the bark of the stock through to the wood ; then a 

 longitudinal one downwards, so that the two incisions shall re- 

 semble the letter T; and, lastly, the bark on each side of the 

 longitudinal incision, is gently raised with a flat instrument, or 

 the handle of the pruning-knife. The bud to be inserted should 

 be selected from the middle of a shoot, and being separated 

 with a slice of the bark about an inch above and below it, the 



