22 BETULACEAE. 
OstryA. Hop Hornbeam. 
(Family Betulaceae). 
Rather deliquescent trees with 
scaly bark: deciduous. Twigs slen- 
der, zig-zag, terete: pith small, 
roundish, continuous, pale. Buds 
solitary, or exceptionally super- 
posed, sessile, ovoid, oblique, with 
half-a-dozen spirally placed striate 
scales, the end-bud lacking. Leaf- 
scars alternate, 2-ranked, some- 
what raised, crescent-shaped or 
half-elliptical, small: bundle- 
traces 3: stipule-scars unequal, 
elongated. Catkins often present. 
Winter-character references:— 
O. carpinifolia. Bodsemann, 70; 
Schneider, f. 163; Willkomm, 27, 
f. 30.—O. virginiana. Blakeslee 
& Jarvis, 332, 410, pl.; Brendel, 
pl. 2; Hitchcock (igiva., (2), we; 
Otis, 80; Shirasawa, 265, pl. 9. 
A spggestive illustrated study 
of the structure of buds as revealed in their unfolding in the 
spring, in which Ostrya figures, is published by Hitchcock 
in volume 6 of the Transactions of the Academy of Science 
of St. Louis. One of many publications on buds superposed 
above the leaves or leaf-scars is by Damaskinos and Bourgeois 
in volume 5 of the Bulletin de la Société Botanique de France: 
in it, reference is made to Ostrya virginiana. 
Scales of staminate catkins long-mucronate: nutlets glabrate, 
fusiform. (1). O. virginiana. 
Seales blunt or abruptly short-pointed: nutlets pubescent 
above, ovoid. (European hornbeam). (2). O. carpinifolia. 
