OBSERVATIONS ON THE NATURE OF SOILS. 



155 



which may be increased by cuttings of the roots that cannot be conveniently pro- 

 pagated in any other way. 



Flowering plants are also propagated by layers. This is only had recourse to 

 with kinds which do not readily strike roots from cuttings. Layering is a safer 

 process ; because the shoot to be rooted is not entirely separated from the 

 parent plant ; but only bent down upon and slightly covered with soil. The 

 buried part of the shoot is tongued, to facilitate the emission of roots ; closely, but 

 not deeply, covered with compost, the point being kept upright. When rooted, 

 they are independent of the old plant, and may be removed at any time. 



Roses, and many other hardy plants, are usually increased by layering ; that 

 tribe of shrubs called American are invariably raised either from seeds or layers. 

 Some few kinds of both stove and greenhouse plants can only be propagated by 

 layering, or by the more scientific means of budding or grafting. 



Hardy or tender herbaceous perennials are increased by cuttings, or layers of 

 their stems, or by simple division of the roots ; and all bulbous and tuberous- 

 rooted flowers are increased by either their seeds or offsets. 



Among the various tribes of exotics, whether tender or hardy, some succeed 

 best by one mode of propagation, others by another ; but they shall be the 

 subject of another paper. 



OBSERVATIONS ON THE NATURE OF SOILS. 



(Continued from page 108.) 



The soils of this country, as stated in my former paper, may be very conve- 

 niently divided into three principal classes, viz. the siliceous or sandy, the aluminous 

 or clayey, and the calcareous or chalky, each of which may, of course, be modified 

 by the presence of vegetable, animal, metallic, or other matters, and thus pro- 

 duce numerous varieties. I shall proceed now to offer a few remarks on some of 

 the more important of these varieties. That different vegetables delight in 

 different soils, is a fact that must be evident to the most common observer ; and 

 it is equally clear that we shall succeed more or less perfectly in the cultivation 

 of plants in proportion to the degree of attention that is paid to the dictates of 

 nature, as regards soil, climate, &c. The horticulturist is therefore frequently 

 obliged to alter and modify his garden-soil, according to the various purposes for 

 which it is intended. The alteration required may be either general or parti- 

 cular : thus, where the soil is naturally too stiff, too light, or too wet, it becomes 

 necessary to have recourse to such operations as the peculiar nature of the soil 

 may require for its improvement. Mr. Loudon in his " Encyclopedia of Agri- 

 culture " says, that " soils may be rendered more fit for answering the purposes of 

 vegetation by* pulverisation, by consolidation, by exposure to the atmosphere, by an 

 alteration of their constituent parts, by changing their condition in respect to water, by 



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