THE LOWER DICOTYLEDONS. 



329 



339; Dog Rose (Rosa canina). There are many kinds of 

 Wild Eoses in Britain, the Dog Rose being the commonest. 



The plant has a woody " stock " which produces suckers ; 

 these are also given off by the roots in some cases. During 

 the first year of growth each shoot usually grows erect to a 

 height of three or four feet and does not branch ; later on 

 the shoot may branch freely and reach a length of ten feet or 

 more in a single season. 



How do the long arched shoots scramble over other plants 

 in a hedge? Sketch a piece of the shoot, showing the 

 shape of the prickles and the direction in which they curve. 



Fig. 133. Longitudinal Section of Flower of Dog Rose. 



Are the prickles deeply embedded in the stem, or can they be 

 pushed off easily ? Each prickle is evidently part of the rind 

 or outer tissue of the stem. 



Sketch a leaf, showing the narrow pointed stipules which 

 adhere to the base of the leaf -stalk ; pull a leaf down and 

 notice the bud, which is protected by the stipules. 



Do all the shoots bear flowers? Do the flowers grow 

 singly or in clusters? Are the flowers found in the thick 

 parts of the hedge, or only at the top and along the sides, 



