288 COMMON TREES AND SHRUBS 



stipules as shown in the diagram. On the lower part of the 

 shoot are numerous small dormant buds. 



The leaves are stalked, and the base decurrent and 

 stipulate. The stipules fall off when the leaf is mature ; the 

 blade is obovate, doubly serrate, and has a rounded or often 

 notched apex. The leaves are folded fan-wise in the bud. 



The flowers are in catkins, and both male and female 

 occur on the same tree. Both are developed in the summer 

 and may be seen on the tree before the leaves fall (Fig. 189, 1). 

 They are thus exposed throughout the winter and open 

 about February in the following year, before the leaves 

 appear (2). The male catkins (1 and 2 m.c) are long and 

 pendulous. On the upper surface of each bract, and united 

 to it, are four scales (5 sc), and three flowers, each flower 

 having a four-lobed perianth and four stamens. The 

 female catkins (1 and 2 f.c.) are small and erect ; the 

 bracts and scales are the same as in the male catkins, but 

 there are only two flowers, the central one not being de- 

 veloped (6 and 7). 



When fertilized the ovary becomes a dry, flattened, one- 

 seeded nutlet. Each bract with its four scales grows and 

 becomes a green five-lobed woody scale, the whole resem- 

 bling a small Pine cone (1 c). The nutlets ripen in the 

 autumn but are retained until the following spring ; 

 the scales then dry and separate and allow the nutlets to 

 fall out, when they may be dispersed by the wind or fall 

 into the stream and be carried some distance before being 

 washed ashore. The old dead blackened cones remain 

 several years on the trees before they are broken off (1 d). 



Note the different years' flowering shoots represented 

 on the branch in Fig. 189, 1. At the growing end are the 

 catkins {f.c and m.c), which will remain on the tree all 

 the winter, and open in the following spring. Below are the 

 ripe female cones (c) of the present season, and lower still are 

 the old cones (d), which shed their fruits the previous year. 



