SYMPODIAL AND MONOPODIAL STE.\fS 



155 



terminal pliytonicr has become converted into a tendril (a). This 

 tendril must be a modified main stem, a modified l)ranch, or a modified 

 leaf, and the decision is perfectly easy when we intjuire as to its relation 

 to tlie axil. In Fig. 432, where the apical j)ortion has become converted 

 into an inflorescence, followed by a cluster of grapes, the determination 

 is the same. 



In all these ilhistrations but one phytonier witli its ])r()(hicts is 

 displayed. By viewing a series of them, we are a})le to determine a 

 number of distinct forms of the sympodial stem, depending upon the 

 order of its branching. In Fig. 433 the branches are borne alternately 

 upon the two sides, and directed alternately to right and left, giving 



fffl*.1 



Figures illustrating sympodial growth: Fig. 428. a, superposed phytonier; I, leaf; c, axillary 

 phytomer or branch. 429. o, turned aside; b, assuming its place. 430. The change complete, the 

 superposed phytomer become lateral, standing opposite the leaf. 431. (The grape) same positions as 

 in 430: a, metamorphosed into a tendril. 432. a, converted into an inflorescence. 433. Alternating 

 sympodial growth. 434. Unilateral sympodial growth. 435. Bifurcating sympodial growth. 



a flexuous appearance to the sympodium; but it must not be forgotten 

 that they may grow quite erect, the leaves alternating regularly upon 

 the two sides and the stem appearing monopodial. No axillary branches 

 will, however, be found. In Fig. 434 the branches develop successively 

 upon the same side. In this case, also, the fully developed portion of 

 the stem is straight and api)ears monopodial, exce])t that the leaves 

 are all upon one side (secmul), but the ])eculiar direction taken by the 

 undeveloped portion toward the tip indicates its true nature, as well 

 as the absence of axillary branches. Fig. 435 represents a sympodial 

 stem on which the branches are borne in ])airs, the obvious result being 

 a double symmetry, each branch successively ending in a pair of 



