54 



MORPHOLOGY OF STEMS. 



109. The two following are organs which may be of axial 

 nature, or may not. This ma}- ordinarily be determined b}- posi- 

 tion. Any direct continuation of 

 stem or branch must be of axial 

 nature, that is, of the nature of stem ; 

 and the same is true of whatever 

 primarily develops in the axil of a 

 leaf. Conversely, whatever subtends 

 a lateral axis or branch ma} r be taken 

 for a leaf or foliar production, being 

 in the place of such. 



110. A Tendril, a thread-shaped 

 and leafless bod}', capable of coiling 

 spirally, and used for climbing (102) , 

 is homologous with stem in Grape- 

 vines (Fig. 92) ; for the uppermost 

 tendril is seen to be a direct continu- 

 ation of the stem. The small bud 

 which appears in the axil of the 

 uppermost leaf will in its growth 

 produce another internode and leaf, 

 or some species more than one, 

 but will terminate in a similar 

 tendril: the present terminal tendril will have then become 

 lateral and opposite the leaf, like the three in the lower part of 



FIG. 92. End of a shoot of the Grape-vine, with young tendrils: a sympodial 

 stem. (See note.) 



FIG. 93. A portion of a stem of Ampelopsis quinquefolia, or Virginia Creeper, with 

 a leaf and a tendril. 



FIG. 94. Ends of the latter, enlarged, showing the expanded tips or discs by which 

 they cling. 



