SYMPODIAL AXD MONOPODIAL STEMS 



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

 tendril must be a modified main stem, a modified branch, or a modified 

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

 to the axil. In Fig. 432, where the apical portion has become converted 

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

 is the same. 



In all these illustrations but one phytomer with its products is 

 displayed. By \aewing a series of them, we are able 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 



^1t 



Figures illustrating sympodial growth: Fig. 428. u, superposed phytomer; t, leaf; <,, axillary 

 phytonier or branch. 420. a, 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. u, converted into an inflorescence. 433. Alternating 

 sympodial growth. 434. Unilateral sympodial growth. 435. Bifurcating s^-mpodial 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 

 ViiW, however, be found. In Fig. 434 the branches develop successi^'ely 

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

 the stem is straight and appears monopodial, except that the leaves 

 are all upon one side (sectind), but the peculiar 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 pairs, the ob^'ious result being 

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



