42 



BLACKTHORN. 



THK LEAF. 



The Icar varies iroin :| to i| inches in length and, at its widest pe)int, 

 troin ^ to J of an inch in breadth. It tapers towards the base and 



ll lias a tinelv serrated edge. The normal torm 



is shown in the diagram. Its colour, at 

 first a delicate pale green, becomes dull and 

 heavy as the season advances. The under- 

 side ot the leat has a dull matt surtace. 

 The mid-rib is prominent. The leaf-stalk 

 is ot a pale green or reddish-green tint on 

 the upper side, and red on the lower side. 

 The leaves are usually tound in a horizontal 

 position, with the tips turned down ; on the new shoots and suckers 

 the leaves are rounder in shape and lie flat, with the angle between 

 the leat-stalk and the twig somewhat acute, so that they point in 

 an upward direction. 



Reference has already been made to the spiral arrangement of- 

 the leaves on shoots of normal development ; wheic the growth of 

 the shoot has been arrested, the leaves often appear in clusters, five 

 leaves radiating in a circle from a group of six buds. The single 

 leaves have usually three buds in the axil of each. 



USUAL eonm 



ik-^r o^f <\Ew SHOOT 



THI-. II.OWLRS. 





The tlowers appear in March and .\[>ril 

 before the leaves. They consist of fi\e [K'tals, 

 hvc sepals, a single carpel tunning the ovary 

 and vellovv-tip[icd stamens. 



The petals are pmx' white and ojien 

 very wide, so that spaces are left between 



