414 



Betulacea Betula. 



ORDER CVIIL BETULACEJE 



Deciduous trees or shrubs with simple alternate stipulate 

 leaves and monoecious flowers in catkins. Perianth none or 

 bract-like. Flowers 2 or 3 together at the base of the bracts 

 of the catkin. Stamens 2 to 5, with forked filaments and 

 divergent anther-cells, or simple with connate anther-cells. 

 Ovary 2-celled ; cells 1-ovulate. Fruit a dry compressed lenti- 

 cular often winged indehiscent nut, by abortion 1 -celled and 

 1-seeded ; seed pendulous. This order is limited to the two 

 following genera, whose species are estimated at about thirty- 

 five. They are scattered over the north temperate zone and the 

 mountains of South America. 



1. BfiTULA. 



Trees or shrubs in 

 which the scales of the 

 female catkin are thin 

 and deciduous, and usu- 

 ally trilobate. Stamens 

 2. The species are con- 

 fined to the northern he- 

 misphere. The name is 

 that used by the ancients. 



1. B. alba. Common 

 Birch (fig. 214). This 

 graceful indigenous tree 

 whose silvery white de- 

 ciduous bark and slender 

 branches render it so 

 effective in a landscape, 

 is represented by several 

 varieties, differing mainly 

 in the foliage from the 

 ordinary form. But the 

 first to claim our atten- 

 tion is B. a. pendula, 

 the Weeping Birch, one 

 of the most distinct and 



Fig. 214. Bctala alba (Common Bi.ch). desirable of this claSS of 



trees, being of moderate size when fully developed. The 



