II] STEMS 21 



the former are not devoid of wood altogether, but that 

 in them the wood does not develope so much as to pre- 

 ponderate over the softer tissues of the structure as is 

 the case with the latter. 



Even branching is not independent of conditions. 

 Most Palms, for examples, although they live for many 

 years, do not branch as usually understood, but it is by 

 no means uncommon to find individuals which have taken 

 to doing so, and many plants which do not usually branch 

 can be compelled to do so by changes of conditions, as 

 exemplified for instance by the nipping off of the terminal 

 buds of strong shoots, pruning, or injuries of other kinds. 



For purposes of description different names are given 

 to stems of various kinds or their parts, by botanists, 

 foresters, and agriculturists. Thus, the hollow stems 

 of Grasses are often called Culms ; short stems bearing 

 rosettes of leaves close to the ground are called Stocks 

 e.g. Plantain, many Ferns, &c. The stout woody stem of 

 ordinary trees is called a trunk, or [the part below the 

 crown of branches is, by foresters, termed] a bole : the lower 

 part of the stem of a felled tree is termed the stool. 



The stems of herbaceous plants present numerous 

 characters according as their surface is smooth, or vari- 

 ously covered with hairs and other outgrowths, well 

 exemplified by contrasting the glabrous stem of many 

 Willows with the softly hairy one (pilose) of others, or 

 the hispid stem of the Borage. Prickles (Bramble), 

 wings (Comfrey), ridges and grooves (Sorrel) are also 

 common on stems. 



Furthermore, the shapes of stems of herbaceous plants 

 demand attention, and this in two ways. In the first 

 place the general shape of the whole stem thin and 

 long, discoid, conical, globose, &c. and, in the second, 

 the shape in transverse section, e.g. square in Labiate 



