TYPES AND KINDS OF STEMS 39 



that of a tall cone. The oval type is represented by certain 

 oaks especially when they grow in the open where they are not 

 crowded and the branch system is free to develop freely. The 

 columnar type is represented by the Lombardy poplar, where there 

 is a central shaft, the leader, and numerous small branches 

 which are nearly erect and nearly parallel with the main axis. 

 The diffuse or deliquescent type is well expressed in the elm. 

 The branching is somewhat dichotomous and diffuse, the main 

 trunk being soon lost. The branching is only an apparent, not 

 a true dichotomy. The buds on the young shoots are alternate 

 and two-ranked, that is, regularly in two rows on opposite sides 

 of the stem. The young shoots tend to be somewhat zigzag, 

 with a bud on the outside of each angle. The axillary terminal 

 bud develops in one direction, while the second bud develops a 

 shoot which diverges in the other direction, thus forming an 

 apparent dichotomy. 



65. Kinds of stems. The great variety of stems may be 

 grouped together under the head of kinds of stems. For example, 

 the floral stem or floral shoot is that part of the stem whose work 

 it is to bear the flower or flowers. The foliage shoot is the portion 

 of the stem which bears the leaves or foliage, and is often very 

 extensive. Specialized stems, or specialized shoots, are those stems 

 which are unusual either because of their peculiar form or because 

 of the work which they perform, as the cactus, the potato tuber, 

 etc. In fact all stems properly speaking are specialized for certain 

 kinds of work. Bud shoots, or buds, for^i another kind of stem. 

 Within each of these kinds of stems there is a considerable variety. 

 The pupil should study a number of each kind. In the study of 

 the floral shoot we are concerned chiefly with the flower, and this 

 topic will be taken up in Chapter XVI. 



FOLIAGE SHOOT. 



66. Erect stems. The erect stems are self -supporting. 

 Trees, the vast majority of shrubs, and many herbs belong to this 

 kind. The main axis is erect for a greater or lesser distance, but 

 the branching often soon displaces the main trunk, and the various 



