678 



CXCVII. BETULACB^. 



Birch. 



t ^ flowers -witti squamiform 



perianth (mag.)- 



Burch. 



Scale and Bquamnlffi' 



of a (J catkin, outer 



face (mag.)* 



Birch. ) 



Scale tearing 3 c? flowers 



(mag.). 



Birch. (Betula alba.) 

 J and 9 catkins. 



Alnus. 



Scale and sqnamulse 



bearing 2 Q flowerSj 



inner face. 



Jacquemont's Birch. 



Scale furnished with its 



3 fruits (mag.). 



Alnus. 



Scale bearing 3 J 



flowers (mag.). 



Alnus glutinosa. 



Scale furnished with 2 



squamulse, and bearing 



3 (? flowers (mag,). 



Alnus. 

 Ripe 9 catkin. 



Alnus. 



Ripe 9 catkin cut 



transversely (mag.)- 



Alnus. 

 Diagram of 2 9 flowers. 



Alnus. 

 gram of ,J flower. 



Jacqnemont'a Birch. 



Vertical section of fi'uit 



(mag.). 



coriaceous scales caducous when full grown {Betula) ; sometimes erect in a corymbose 

 raceme, with the scales at first fleshy, then woody and persistent {Alnus) ; scales 

 sessile, 3-lobed and flowered {Betula), or entire and each accompanied by 4 lateral 

 squamules, and 2-flowered {Alrms), Perianth 0. Ovaet sessile, with twol-ovuled 

 cells, of which one is often empty ; stigmas 2, terminal, sessile, elongate, filiform ; 

 ovules pendulous from the septum a little below its top, anatropous. StkoSilus 

 formed by the enlarged scales. Nuts winged or annular, 1-celled and 1-seeded. 

 Seed inverted; testa membranous, thin. Embryo exalbuminous, straight; cotyledons 

 plane, foliaceous in germination ; radicle superior. 



* Betula. 



GENERA. 

 * Alnus, 



Clethropais. 



We shall indicate tlie affinities of Betulacem with CupuUferce and Myricecb under those families. 

 They approach Ulmacece in the stamens being opposite to the calyx-lobes^ in the 2-celled ovary and 



