DEVELOPMENT OF PLANTS 



399 



with their lint-like masses. The name cottonwood is popularly 

 applied to several of the poplars because'of the cotton-like clusters 

 of seeds that emerge from their aments. 



139. Fagales, the Beech Order. This order includes many 

 of the most important hard-wood trees of the temperate regions, 

 comprising the family of the birches, with such representatives 

 as the American hornbeam (Carpinus), hop hornbeam (Ostrya), 

 hazel (Corylus), birch (Betula), alder (Alnus) and the beech 

 family, which includes the chestnut (Castanea), beech (Fagus) 

 and oak (Quercus), The inflorescence is more commonly an 

 ament as in the preceding order (Figs. 298, A ; 299, A}, although 



FIG. 298. Flowers and fruits of the birch family, order Fagales: A, 

 inflorescence of hornbeam (Carpinus} s, staminate ament; p, pistillate 

 ament. B, staminate clusters from ament of alder (Alnus}, each flower 

 consisting of four stamens attached to a four-parted perianth, pr. C, 

 upper view of the same cluster, showing the numerous bracts associated 

 with the flowers. D, fruit of Carpinus attached to the greatly enlarged 

 three-lobed bract. E, flower cluster of hazel (Corylus^b, bract encircling 

 the ovary and within a more delicate bract, pr, adnate to the ovary; s, 

 stigma. F, fruit of Corylus, the bract, b, in E has grown out into a tubular 

 beaked structure that completely envelops the nut. 



