THORNY SHRUBS 233 



ovate, serratulate. The best distinction from Primus spinosa 

 lies in the paler epidermis, more prominent, scattered 

 lenticels, the polygamo-dioecious flowers and their structure, 

 and the curved venation of the leaves, which are sub- 

 opposite. 



OO Twigs, buds, leaf -scars and leaves alter- 

 nate; shoots hairy, more or less angular; 

 twigs dark brown-red to glistening black'. 

 Venation pinnate. Floivers white or pink, 

 rosaceous. 



Tiuigs dark brown-red to pale brown, 

 passing to glistening black often filmed 

 with grey. Leaves ovate, serrulate. 

 Flowers small tufted and very early. 

 Fruits blue-black with waxy bloom. 



Prunus spinosa, L. Blackthorn (Fig. 10). A shrub 

 8 10 feet high, very stiffly branched, and dark, almost 

 black, in hue, showing up the clustered flowers in early 

 spring. The twigs may vary to paler brown, and the 

 branches may have a silvery-grey film as the epidermis 

 peels. 



Prunus insititia is a variety with browner branches, 

 fewer spines, and with fruit varying to yellow in colour. 



Twigs olive-green to red-brown or pur- 

 plish, passing to grey or blackish-grey 

 and fissured on the branches. Leaves 

 angular, lobed. Flowers in corymbs, 

 white or pinkish. Fruit oblong, red, 

 tipped with remains of the calyx, &c. 



Cratcegus Oxyacantha, L. Hawthorn (Fig. 117). It is 

 frequently met with as a shrub, and would then come here: 

 we have dealt with it as a small tree (see p. 199). Its dense 

 and stiffly branched, and usually very thorny habit ; the 

 olive-green to red-brown or purplish branches sometimes 

 with dashes of bright yellow ; the older stems grey to 



