XIX. 



BETULA ALBA. 



Common Birch. 



Class XXI. MoNCECiA.— Orc?er VI. Polyandria. 



Nat. Ord. Amentace^e. 



Gen. Char. Barren flowers in a cylindrical catkin ; the 

 scales temate, the middle scale bearing the stamens. 

 Fertile flowers in a catkin whose scales are imperfectly 

 three-lobed, three -flowered. Germen compressed, with 

 two cells, one of which is abortive ; styles two. Fruit 

 membranous, winged, one-celled. 



Spec. Char. Leaves ovate-deltoid, acute, doubly ser- 

 rated, nearly smooth. 



SYNONYMES. 



Desckiption. — The common Birch is a graceful tree, growing 

 in a favourable soil to the height of forty or fifty feet. The 

 trunk is straight, cylindrical, without knots, and dividing 

 towards the top, into numerous flexible, pendent branches ; the 

 bark has a silvery appearance, and when old peels off trans- 

 versely. The leaves are alternate, petiolate, ovate, somewhat 

 deltoid, acute, irregularly serrate, nearly smooth, and shining. 



