CATKINS 



79 



become completely developed ; the other will be 

 squeezed out of existence by its neighbours, and the 

 ripe ovary will be one-celled and one-seeded. Behind 

 each ovary are two minute bracts, lying side by side 

 against the scale. These can only be made out by 

 close examination ; they become plainer during the 

 ripening of the seed. 



On the same trees which yield the catkins and 

 cones, last year's cones, black 

 and woody, and perhaps the 

 cones of the year before last, 

 can be seen on the ends of 

 some of the branches. When 

 the cones come to maturity, 

 their scales part and the 

 fruits are exposed. By March 

 many of last year's fruits 

 have been shaken out, but 

 plenty can still be found on 



the tree. Break a ripe cone across. You will find the 

 central stalk extremely tough. From it radiate the 

 woody scales, each bearing a pair of angular fruits 

 upon its upper surface. 



We saw that the Birch-fruits were winged ; why 

 are not the Alder-fruits winged too? Does this 

 invalidate the explanation that the wing is useful in 

 dispersal ? I think not ; it is only a negative exception. 

 A wooden leg is used to enable a man to walk when 

 he has lost his natural leg. If you saw a one-legged 

 man walking with a pair of crutches, and no wooden 

 leg at all, would that shake your belief in the motive 

 for wearing wooden legs ? I shall have something 



FIG. 21. Two flowers from a 

 cone of the Alder, showing a 

 large outer scale, and two 

 pairs of smaller bracts, one pair 

 to each flower. Magnified. 



