432 



THE FAGALES 



phylls are usually developed upon the same plant. Several bracts 

 are usually associated with sporophylls (Figs. 298, B-F; 299, 

 B-E) so that the flowers are of a higher type than the willows. 

 The innermost of these bracts is often of a delicate structure and 

 has been referred to as a primitive form of the calyx (Fig. 298, 

 B, pr) and when present in the pistillate flowers it adheres to 



Fig. 298. Flowers and fruits of the birch family, order Fagales: A, in- 

 florescence of hornbeam {Carpinus) — j, 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. D, 

 fruit cluster of hazel (Corylus) — b, bract encircling the ovary and within a 

 more delicate bract, pr, adnate to the ovary; ^, stigma. F, fruit of Corylus, 

 the bract, b, in E has grown out into a tubular beaked structure that com- 

 pletely envelops the nut. 



the ovary (Figs. 298, E, pr; 300, B, pr). The pistils are pro- 

 vided with long delicate stigmas and are compound, containing 

 several ovules but only one usually matures. The wall of the 

 ovary develops into a tough coat about the seed, forming a fruit 



