CLASS XX. ORDER XIII. 109 



serrate acuminate pubescent beneath. ^ • g-w.— 

 sylvatica^ leaves glabrous obsoletely serrate. \ - 



Castanea. Polygamous. Staminate flowers — 

 ament naked, linear : corol 5-petalled : stamens 10 

 to 20. Pistillate flowers — calyx 5 or 6-leaved, mu- 

 ricate : germs 3 : stigmas pencil-form : nuts 3, 

 Avith coriaceous putamen, inclosed in the calyx be- 

 coming echinate. 50. : 9 — vesca-americana, (ches- 

 nut) leaves lance-oblong glabrous, sinuate-serrate. 



Betula. Staminate flowers — ament imbricate, 

 scales peltate 3-flowered : calyx a scale : stamens 

 10 to 12. Pistillate flowers — calyx a 2-flowered 

 scale : seed I, winged. 50. 99 — /la/iyracea^ (canoe 

 birch, or paper birch) leaves ovate acuminate dou- 

 bly-serrate, veins hirsute beneath. I2 '—po/iulifoliaf 

 (white birch, broom birch) leaves deltoid long acu- 

 minate very glabrous. >2 . — le?ita, (black birch) 

 leaves heart- ovate sharp-serrate acuminate, petioles 

 and nerves hairy beneath. Ij . A variety, lutea^ 

 (yellow birch) bark yellowish. 



Carpinus. Ament imbricate. Staminate flow- 

 ers — calyx-scales ciliate : stamens 10. Pistillate 

 flowers— calyx-scales 2-flowered : corol 3-cleft : 

 nut ovate sulcate. 50. 99 — americana^ (hornbeam) 

 scales of the pistillate ament 3-parted with the in- 

 termediate division lance-ovate, leaves unequally- 

 serrate, h . 



OsTRYA- Ament imbricate. Staminate flowers 

 —calyx a scale : filaments ramose. Pistillate flow- 

 ers — ament naked : capsules inflated, imbricate, 

 with one seed at its base. 50. 99 — virginka^ (hop 

 hornbeam) leaves oblong-ovate acuminate, ^i . g. 



CoRYLus. Staminate flowers — ament imbricate : 

 calyx a scale : stamens about 8. Pistillate flowers. 

 — calyx 2-parted, lacerated ; styles 2 : nut ovate, 

 surrounded by and included in the permanent leaf- 



