22 



BOTANY 



PART I 



is often spoken of as the AXIS ; the portions 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 be- 

 come strongly marked (Labiatae). 



In some cases the growth in length of a 

 shoot continues for a longer time at certain 

 intermediate points by means of INTERCALARY 

 <;ROYVTH. Such regions of intercalary growth 

 are generally situated at the base of the inter- 

 nodes, as in the case of the Grasses. A dis- 

 placement 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 



Kic;. -JO. Xaiiiolus I'/'Icraiidi, . ., i , T i e j A i i_ 



each axillary shoot (a) of lts . subtending leaf, and so apparently have 

 bearing its subtending leaf its origin higher on the stem; or a subtending 



fruit*"' 1 iSt'si""" 1 ' 8 '" * leaf ' in the COU1>Se * itS growth* ma J Can 7 its 



axillary bud along with it, so that the shoot 



which afterwards develops seems to spring directly from its subtend- 

 ing leaf ; or, finally, the subtending leaf may 

 become attached to its axillary shoot, and 

 growing out with it, may thus appear to spring 

 from it (Fig. 20). 



Iu the annual growth in length of a shoot of a tree, 

 i.e. the increment formed during one vegetative period, 

 tlio loAvest internodes which 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 protection 

 against loss of water in our latitudes, the buds 

 of shrubs and trees are usually invested, in 

 winter, with scale-like leaves or BUD-SCAL1> 

 (Fig. 21). These are rendered still more effec- 

 tive as protective structures by hairy outgrowths 

 and excretions of resin and gum, and also by 

 the occurrence of spaces filled with air between 

 the scales. Not infrequently the subtending 



^ J & 



leaf takes part in the protection of its axillary 



bud, the base of the leaf-stalk, after the leaf 



itself has fallen, remaining on the shoot as a 



cap-like covering for the winter bud. The buds of tropical plants, 



which have to withstand a dry period, are similarly protected ; but 



I.- tin 



, 



Fin. 21. Winter bu<is of the 



Beech (*,.,"'> 



*. Bud--to* (Nat. 



