BETULACE.E 203 



CONSPECTUS OF THE NORTH AMERICAN SPECIES. 



Leaves oblong-lanceolate, acuminate or acute at apex. 1. O. virginiana (A, C). 



Leaves elliptic or obovate, acute or rounded at apex. 2. O. Knowltonii (F). 



1. Ostrya virginiana K. Koch. Hop Hornbeam. Ironwood. 



Leaves oblong-lanceolate, gradually narrowed into a long slender point or acute at apex, 

 narrowed and rounded, cordate, or wedge-shaped at the often unequal base, sharply serrate, 

 with slender incurved callous teeth terminating at first in tufts of caducous hairs, when they 

 unfold light bronze-green, glabrous above and coated below on the midrib and primary 

 veins with long pale hairs, at maturity thin and extremely tough, dark dull yellow-green 

 above, light yellow-green and furnished with conspicuous tufts of pale hairs in the axils of 

 the veins below, 3'-5' long, l^'-2' wide, with a slender midrib impressed and puberulous 

 above, light yellow and pubescent below, and numerous slender veins forked near the 

 margins; turning clear yellow before falling in the autumn; petioles hairy about i' long; 

 stipules rounded and often short-pointed at apex, ciliate on the margins with long pale 

 hairs, hairy on the back, about \' long and ' wide. Flowers: staminate aments about 

 ' long during their first season, with light red-brown rather loosely imbricated scales nar- 



Fig. 192 



rowed into a long slender point, becoming when the flowers open 2' long, with broadly 

 obovate scales rounded and abruptly contracted at apex into a short point, ciliate on the 

 margins, green tinged with red above the middle, light brown toward the base; pistillate 

 aments slender, about \' long, on thin hairy stems, their scales lanceolate, acute, light 

 green, often flushed with red above the middle, hirsute at the apex, decreasing in size from 

 the lowest. Fruit: nuts \' long, about \' wide, rather abruptly narrowed below the apex, 

 their involucres in clusters l^'-2' long and f '-!' wide, on slender hairy stems about 1' in 

 length. 



A tree, occasionally 50-60 high, with a short trunk 2 in diameter, usually not more than 

 20-30 tall, with a trunk 18'-20' thick, long slender branches drooping at the ends and 

 forming a round-topped or open head frequently 50 across, and slender, very tough branch- 

 lets, light green, coated with pale appressed hairs when they first appear, becoming light 

 orange color and very lustrous by midsummer, glabrous, dark red-brown and lustrous during 

 their first winter, and then growing gradually darker brown and losing their lustre; or cov- 

 ered like the petioles and peduncles with short erect glandular hairs (var. glandulosa Sarg.)- 



