24 



HOW PLANTS GROW YEAR AFTER YEAR. 



of the preceding one. There are old trees even, which consist of a simple, un- 

 branched stem. Palm-trees, such as our Southern Palmetto (Fig. 79) are of thia 



kind. But more commonly, as stems grow they multiply them- 

 selves by forming 



53. Brandies, or side-shoots. These are formed both by 

 roots and by stems. Poots generally branch much sooner than 

 stems do. See Fig. 4, 20, 30, &c. 



54. Roots send off their branches from any part of the 

 main root, or start from any part of a stem lying on or in the 

 soil ; and they have no particular arrangement. 



bb. But the branches of stems spring only from particular 

 places, and are arranged on a regular plan. They arise from 

 the Axil of a leaf and nowhere else, except in some few pe- 

 culiar cases. The axil (from a Latin Avord meaning the 

 armpit) of a leaf is the hollow or angle, on the upper side, 

 where the leaf is attached to the stem. As branches come 

 only from the axils of leaves, and as leaves have a perfectly 

 regular and uniform arrangement in each particular })lant, the 

 places where branches will appear are fixed beforehand by the 

 places of the leaves, and they must follow their arrangement. 

 In the axils, commonly one in each, branches first appear in 

 the form of 



bQ. Buds. A Bud is an undeveloped stem or branch. If 

 large enough to have its parts distinguishable, these are seen- 

 to be undeveloped or forming leaves ; and large buds which 

 are to stand over winter ai'e generally covered with protect- 

 ing scales, — a kind of dry, diminished leaves. 



57. Terminal Bud. So the plumule or first shoot of the 

 embryo (see Fig. 22, &c.) is a bud. But this first bud makes 

 the main stem, and its growth, week after week, or year after 



year, carries on the main stem. Palms (as Fig. 79) grow in this way, by this bud 



only. Being always on the end of the stem, that is, terminating the stem, it is 



called the Terminal Bud. 



58. Axilhiry Buds. But the buds which are to form branches appear on the 



sides of the stem ; and since they are situated in the axils of the leaves, as just ex- 



