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 





wm? '1 W" 



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

 florescence 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. D, 

 fruit 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 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 



