RUNNERS, TENDRILS, ETC. 



103 



184. An Offset is a similar, but short, prostrate branch, with a tuft 

 of leaves at the end, which, resting on the ground, there takes root, 

 and at length becomes independ- 

 ent; as in the Houseleek. 



185. A Tendril is commonly a 

 thread-like, leafless branch, capable 

 of coiling spirally, by which' some 

 climbing plants attach themselves 

 to surrounding bodies for support ; 

 as in the Grape-vine (Fig- 1G1). 

 But sometimes tendrils belong to 

 the leaves, as in the Pea; when 

 they are slender prolongations of 

 the leafstalk. Some tendrils cling 

 by hooking their tips around the 

 supporting object. Others, such as 

 those of the Virginia Creeper (Fig. 

 1G2, 163), commonly expand the 

 tips of the tendrils into a flat disc, — 

 much as do many aerial rootlets (as 

 those of Ivy) when subservient to 

 the same office, — which firmly ad- ,61 



heres to walls or the bark of trees, thus enabling the plant to ascend 

 and cover their surface. As soon as they are attached, tho vtj^lril 



FIG. 161 End of a shoot of the Grape-vine, with young tendrils 



FIG 162. A portion of a stem of Ampelopsis, or Virginia Creeper, with a leaf and a tend iL 



FIG. 163 Ends of the latter, enlarged, showing the expanded tips by which they cling. 



