AMENTACE2E. 



751 



1. Common Alder. Alnus glutinosus, Linn. (Fig. 903.) 

 (Betula Alnus, Eng. Bot. t. 1508.) 



A moderate- sized tree, of a dark hue. 

 Leaves stalked, broadly ovate or orbi- 

 cular, sharply toothed, and occasionally 

 lobed, glabrous, or with a little down in 

 the axils of the veins on the under side. 

 Catkins 2 or 3 together, in terminal 

 clusters or small panicles ; the males 

 long, loose, and drooping; the females 

 not half an inch long, with the styles 

 slightly protruding. In the fruiting cat- 

 kin the scales are not unlike those of a 

 miniature fir-cone. 



In wet woods, and borders of streams, 

 and wet pastures, in Europe and west- 

 ern Asia, not extending to the Arctic 



Circle. Abundant in Britain. Fl. early spring, before the leaves are 

 fully out, the catkins having been formed the previous autumn. 



Fig. 903. 



III. BIRCH. BETULA. 



Flowers monoecious, the males in cylindrical catkins, usually pen- 

 dulous, with broad, shortly stalked scales. Stamens 8 to 12 within 

 each scale, the anthers on very short filaments, the cells distinct, some 

 with a small scale underneath, and all irregularly arranged in 3 flowers. 

 Female catkins cylindrical and compact, each scale with 2 small scales 

 inside, and 3 or rarely more flowers. No perianth. Ovary flat, with 2 

 styles and 2 cells, with a pendulous ovule in each. In the fruiting 

 catkin the scales (formed of the catkin-scale, with the 2 inner ones 

 combined) are somewhat enlarged, and 3-lobed, falling off with the 

 nuts, which are small and seed-like, flat, surrounded by a scarious 

 wing. 



A small genus, confined to the northern hemisphere, and not reach- 

 ing the tropics. 



Tree, with broadly ovate, usually pointed leaves 1. Common B. 



Shrub, with small, orbicular leaves ....*..., 2. Dwarf _Z?. 



1. Common Birch. Betula alba, Linn. (Fig. 904.) 

 (Eng. Bot. t. 2197. JB. glutinosa, Bab. Man.) 

 An elegant tree, with slender, often gracefully drooping branches, 



