366 THE BIRCH. 



THE CATKINS . 



Male and female catkins are found on the same tree. The male 

 catkins are formed during the summer, and remain on the tree 

 throughout the winter months. They grow in pairs (sometimes 

 singly, sometimes in groups of three) at the ends of the slender twigs, 

 and their habit of standing out from the twig (< shaped) which 

 supports them renders them very conspicuous. 



By the middle of April they have grown to one or one and a 

 half inches in length, and become pendulous, while their red-brown 

 colouring affects the appearance of the tree nearly as much as do the 

 young leaves ; they are now mature and shed quantities of pollen. At 

 this time of year the female catkins, though more numerous, are less 

 noticeable, and appear merely as small thin spikes of green, standing 

 erect between the pairs of young leaves. Latej on the colour of 

 the stigmas gives them a reddish tinge. 



CONSTRUCTION OF THE CATKINS. 



The Male catkins are compact, cylindrical in form, and pointed. 

 Each catkin consists of a central axis, round which are arranged a 

 number of bracts or scales. These overlap one another so long as 

 the catkin is immature, but become separated in time by the elonga- 

 tion of the axis to which they are attached. Every scale bears on 

 its inner side three florets ; the florets have two stamens apiece, each 

 with a forked filament ; this gives the appearance of there being 

 twelve stamens below each scale. When the catkin is ripe the 

 stigmas project all round the scale. 



The Female catkins are invisible during the winter, hidden under 

 the scales of the lateral buds on the branch which terminates in the 

 male catkins. As the buds open, and the leaves unfold, the catkins 



