BIRCH FAMILY 



branchlets of the year. 



stipulate. Apparently they often appear in pairs, but these 

 pairs are really borne on spur-like two-leaved lateral 

 branchlets. 



The flowers are monoecious, opening with 

 or before the leaves and borne in three- 

 flowered clusters in the axils of the scales of 

 drooping or erect aments. Staminate aments 

 are pendulous, clustered or solitary in the 

 axils of the last leaves of the branch of the 

 year or near the ends of the short lateral 



They form in early 

 autumn and re- 

 main rigid dur- 

 ing the winter. 

 The scales of 

 the staminate 

 aments when 

 mature are broadly ovate, 

 rounded, yellow or orange 

 color below the middle, 

 dark chestnut brown at 

 apex. Each scale bears 

 two bractlets and three 

 sterile flowers, each flower consisting of a 

 sessile, membranaceous, usually two-lobed, 

 calyx. Each calyx bears four short fila- 

 ments with one-celled anthers or strictly, 

 two filaments divided into two branches, 

 each bearing a half-anther. Anther cells 

 open longitudinally. The pistillate aments 

 are erect or pendulous, solitary ; terminal 

 on the two-leaved lateral spur-like branch- 

 lets of the year. The pistillate scales are 



Branch of Red Birch, 

 Betuia iiigra, Show- 

 ing the Staminate 

 Aments as they Ap- 

 pear in Winter. 



Sweet Birch, Betuia 



Staminate 

 Aments 3' to 4 long. - 



lenta. Staminate oblong . ovate thrCC-lobed, pale yellow green 



' 



often tinged with red, becoming brown at 

 maturity. These scales bear two or three fertile flowers, 

 each flower consisting of a naked ovary. The ovary is 



