610 



BOTANY 



PART II 



MOST IMPORTANT GENERA. Alnus glutinosa, the Alder, is a prominent tree 

 of damp woods, and is also distributed in swamps and by the banks of streams. 

 The inflorescences are already evident in the autumn as stalked catkins, the male 

 long and pendulous, the female erect and short. Male flowers P4, A4 ; a dichasium 

 of three flowers adherent to each bract (Fig. 603). The female flowers are in 



Fio. 602. Juglans regia. 1, Branch with young leaves, male catkins and at the tip female flowers. 

 2, Male flower. 3, Female flower. 4, Fruit with the outer layer of the pericarp in part 

 removed. ( nat. size.) 



pairs, their bracteoles adhering to the bract to form the five-lobed, persistent, 

 woody scale of the cone. Alnus incana is distinguished by its leaves being grey 

 and hairy below. Betula verrucosa (Fig. 604), the Birch, has a white bark and long 

 stalked, triangular leaves. When young, all the parts are covered with numerous 

 glandular hairs which give the plant an aromatic, resinous odour. The male 

 inflorescences are formed in the autumn of the previous year, singly or a few 

 together, at the tip of shoots of unlimited growth. Flowers P2, A2,; in dichasia 



