22 



BOTANY 



PART I 



Further Development of the Shoot. — :The processes of develop- 

 ment, which result in the production of new members at the apex 

 of a shoot, are followed by their increase in size and further growth. 

 This growth is usually introduced by the vigorous elongation of 

 the segments, which is spoken of as growth in length, while at the 

 same time the buds expand. The zone of most rapid growth in 

 length is at some distance from the growing point. The growth 

 in length and consecjuent elongation of the shoot is in some cases 

 so slight that the leaves remain close together, and leave no free 

 spaces on the stem, thus forming so-called short SHOOTS. The 

 same plant may bear ordinary elongated shoots and short shoots. 

 The duration of life of the latter is usually shorter^, and they fre- 

 quently do not branch, and take no part in 

 the permanent branch system of the tree. This 

 is seen in the Larch, in which the short shoots 

 Avith crowded needle-shaped leaves are borne on 

 elongated shoots. 



The stem of a shoot, as contrasted with the 

 leaves, is often spoken of as the AXIS ; the por- 

 tions of the stem axis between the insertions 

 of the leaves are termed the internodes, and 

 the parts of the axis from which the leaves 

 arise, the nodes. When the base of the leaf 

 encircles the stem, or when several leaves take 

 their origin at the same node, the nodes often 

 become strongly marked (Labiatae). 



In some cases the growth in length of a 

 each axillary shoot («) bear'- shoot continues for a longer time at certain 

 iiig its subtending leaf (<), intermediate points by means of intercalary 



and terminating in a fruit. o i • r • , ^ ■, 



(Nat. size.) GROWTH. buch regions of mtercalary growth 



are generally situated at the base of the inter- 

 nodes, as in the case of the Grasses. A displacement from the 

 position originally occupied by the members of a shoot frequently 

 results from intercalary growth. A bud may thus, for example, 

 become pushed out of the axil of its subtending leaf, and so apparently 

 have its origin higher on the stem ; or a subtending leaf in the 

 course of its growth may carry its axillary bud along with it, so that 

 the shoot which afterwards develops seems to spring directly from its 

 subtending leaf ; or, finally, the subtending leaf may become attached 

 to its axillary shoot, and groAving out with it, may thus appear to 

 spring from it (Fig. 20). 



Ill the annual growtli in length of a .shoot of a tree, i.e. tlie increment formed 

 during one vegetative period, tlie lowest internodes wliieli intervene between 

 the bud -scales are very short. By means of the closely crowded scars of the 

 bud-scales the limits of the shoots formed in successive years can be determined. 



Resting Buds. — As a means of i^rotection against loss of water 



Fio. 20. — Samoltis vcderandi, 



