52 THE BOOK OF NATURE STUDY 



THE DOG ROSE (Rosa canina, L.) 



The wild Roses of Britain are represented by numerous more 

 or less distinct kinds which have been variously grouped by 

 systematic botanists, some recognising only a few species with 

 numerous varieties, while others regard most of the minor forms 

 as species. The occurrence of these numerous forms must be 

 borne in mind when differences in detail are found between the 

 specimen studied and the following description. Some details, 

 which vary in the different forms of the Dog Rose, have been 

 passed over to make the account serviceable as a guide to the 

 study of almost any specimen. 



The Dog Rose is a shrub, the shoots of which are profusely 

 branched and persist from year to year. The older woody stems 

 attain a considerable thickness, but no single main stem increases 

 beyond the others in thickness, as in trees as distinguished from 

 shrubs, nor does the plant reach the size of a tree. The long 

 branches either hang down or straggle over neighbouring shrubs, 

 from which they obtain support. The prickles of the Rose are 

 of assistance in this. They are bulky structures of the nature of 

 hairs that arise from the outer layers of the stems and leaf-stalks. 

 As is shown in the plate, the prickles are flattened from side to side 

 and taper from an oval base to a sharp point ; they are curved so 

 as to point towards the base of the stem. It is easy to see that, 

 while they offer no obstruction to a branch of the Rose growing 

 up between other herbage, they will interfere with its being 

 pulled back from the position it takes up. The general appearance 

 and mode of growth of the plant should be studied in the field, 

 while shoots, including both the growth of former years and the 

 foliage and flowering shoots of the current season, should be cut 

 off and brought home for detailed study. This is best done in 

 July when the plant is in full flower, but later in the season the 

 fruits must be collected and examined in order to complete the 

 study of the plant. 



The parts of the shoot which grew in former years can be dis- 

 tinguished at once from the growths of the present season. The 

 older parts are brown, from the presence of a layer of cork pro- 

 tecting the surface, and they have lost their leaves. The small 



