250 PMAGTIGAL BOTANY. 



Both sorts, sterile and fertile flowers, in aments, 

 heads, or spikes 790 



TST. Involucre 2- to 3-flowered, prickly. Stamens 8-15. 



788 

 Involucre 1- to 2-flowered, smooth. Stamens 6-12. 



789 



788. Sterile flowers in long, cylindrio aments, interrupt- 

 edly clustered in them; calyx 5- to 6-parted ; stamens 8-15. 

 Fertile flowers in pairs, or threes, in a prickly, scaly involu- 

 cre, forming a bur, which at length encloses 1-3 coriaceous 

 nutlets, and, at maturity, opens by 4 valves. Leaves oblong, 

 or oblong-lanceolate, serrate with pointed teeth. Castanea. 



Sterile flowers in small heads, on drooping, axillary 

 pcnduncles. Fertile flowers commonly in pairs at the apex 

 of a short peduncle in a soft-prickly involucre, formed of 

 numerous, united awl-shaped bractlets. Nut sharply 3-cor- 

 nered. Leaves oblong-ovate, taper-pointed, toothed. 



Fagus ferruginea, Ait. 



789. Involucre 1-flowered, of many imbricated, small 

 scales, forming a cup around the base of the hard arid 

 rounded nut. Sterile flowers clustered in slender and naked, 

 drooping aments, without bracts. Stamens 6-12. Quercus. 



Involucre 1- to 2-flowered, of 2-3 confluent scales, 

 which become leafy-coriaceous, much enlarged and cut or 

 torn at the apex, enclosing a bony nut. Sterile flowers in 

 drooping cylindric aments ; the concave bracts and the 2- 

 cleft calyx united into 3-lobed scales. Stamens 8 ; anthers 

 1-celled. Oorylus. 



790. Sterile flowers in long aments with imbricate scales. 



791 

 Sterile aments none of this sort 795 



791. Anthers bearded at the apex. Sterile flowers in 

 aments, their scales simple, with 12 stamens. Fertile aments 

 flaccid. Fruit a small nut. Leaves oblong-ovate, serrate. 



792 



Anthers not bearded at the apex , 793 



79S. Involucral scales of the fertile aments large, 3- 

 lobed, the middle lobe much largest, unequally seirate- 

 toothed on one side ; the scales in pairs, each 2-flowered. 



