390 TREES AND SHRUBS. 



lobed leaves, (4) the less marked flattening of the leaf-stalk, (5) the 

 slight hairiness of the bracts, (6) the four slender yellow stigmas. It 

 grows very quickly and may become a hundred feet high in forty years, 

 with a massive trunk. The White Poplar, like the Black, has a 

 "pyramidal" variety. 



383. There are many different Willows, including varieties 

 and hybrids, in Britain, but the commoner kinds are fairly easy 

 to identify, and there are many points on which most of our 

 Willows agree pretty closely. The leaves are alternate, with 

 stipules, and usually have prominent cushions which run 

 down the stem for some distance. The buds, which are 

 generally pressed against the stem, may either produce long 

 shoots bearing leaves, or short shoots which end each in a 

 catkin ; the short shoot sometimes bears a few leaves below 

 the catkin (e.g. Crack Willow) . Each bud shows on the outside 

 only one large rolled-up scale ; sometimes there are two small 

 buds inside this scale, one on each side of the ordinary bud. 



The catkin-bracts have silky hairs on the outer surface, 

 and each flower has a green or yellow nectary, or two 

 nectaries, at the base of the stamens or pistil on the side 

 nearest the axis of the catkin. The male flower has few 

 stamens (two to five), the number (though not constant) 

 serving to distinguish some of the species ; the anthers are 

 yellow, the filaments long. The female flower has a pear- 

 shaped ovary, generally carried on a stalk ; the tapering 

 upper end runs into a style with two stigmas which are 

 sometimes branched, and the ovary has the same structure 

 as in Poplars. Bees visit the flowers for honey and pollen. 

 The capsule opens by two valves, as in Poplars, and the seeds 

 have a tuft of hairs arising from the seed- stalk. 



Willows may be roughly divided according to the presence 

 or absence of long slender quickly- growing shoots (osiers) 

 which often grow about nine feet long in a single season, or 

 according to the breadth or narrowness of the leaves. 



384. Hazel (Corylus avellana) is a small tree, rarely 

 over 15 ft. high. There is usually no main trunk, but 

 several branches starting at the base of the tree. From the 

 base of the shoot arise numerous erect quickly- growing 

 branches (" stool-shoots "), and similar branches (" suckers ") 

 are often given off by the root ; the stool- shoots and suckers 



