BIRCHES 



235 



Stigmas purple-red. Fruiting catkins pendent or not, thick 

 cylindroid, 15 40 cm. long : stalk 7 10 mm. Scales 



Fig. 73. Birch, Betula alba. A, shoot with $ and ? catkins. 

 5, bract, bracteoles, and perianth, of 3 , from within, with stamens re- 

 moved; C, a stamen; D, floral diagram of B-, E, bract, bracteoles and 

 flowers of ? , from within ; F, the same with flowers removed ; 6r, the 

 same at ripeness of seed; H, floral diagram of E. &, bract, a, /3, 

 bracteoles of flower 1, or bracts of flowers 2, 3 (Ei). 



triple, on a broad short stalk, the lateral angular, hairy 

 and ciliate. The detailed analysis is shown in Fig. 73. 



[Betula verrucosa, Ehr., is distinguished by some as a 

 species by its more waxy twigs, covered with minute 

 verrucosities ; more glabrous leaves and shoots, the former 

 thinner and less leathery, and with longer points ; and 

 minor differences in the fruit-scales, &c. 



B. nana, L., the Dwarf Birch of the North, is shrubby 

 and bears much smaller catkins, 10 20 mm. or so, with 

 less deciduous scales.] 



** Catkins of ? flowers ellipsoidal and stiff, 

 stalked, and collected in branched race- 

 mose groups of three or four. Scales 

 5-lobed, becoming woody, and persisting 

 after the fruits fall. The $ catkins at 

 length pendulous. 



