OAK FAMILY. 301 



J. nigra. BLACK W. Large tree, commoner W. & S. : stalks and shoot* 

 not clammy, minutely dovvny ; leaflets smoothish, ovate-lanceolate, serrate ; 

 fruit spherical. 



* * Planted from the Old World : husk friable, separating when dry from the 



roundish and smoot/tish thin-shelled nut. 



J. rdgia, ENGLISH WALNUT, so called, but native of Asia : leaflets oval, 

 entire, smoothish; fruit ripens sparingly in Middle States. 



2. CAKYA, HICKORY. (Greek name of the Walnut, applied to these 

 North American trees.) Fl. in rather late spring : nuts fall in autumn. 

 1. Sterile catkins in a sessile cluster : leujlels 13 - 15, short-stalked: nut edible. 



C. Oliv8ef6rmis, PECAX-XUT. Along rivers, from Illinois S. : leaflets 

 oblong-lanceolate, taper-pointed ; nut cylindrical-oblong, olive-shaped, the seed 

 delicious. 



2. Sterile catkins 3 or more together on a common peduncle: leajlets sessile or 

 nearly so, of 5-9 or rarely 11-13 Leajitts : nut globular or short-oval. 



* Nuts sweet-tasted and edible (rhzjuckory-nuts of the market) ; the husk splitting 



into 4 thick and hard valves : buds large, of about 10 scales. 



C. alba, SHELL-BARK or SHAG-BARK H. Commonest E. : bark of old 

 trunks very shaggy, separating in rough strips ; inner bud-scales becoming very 

 large and conspicuous on the young shoot ; leaflets 5, the 3 upper much larger 

 and lance-obovate ; nut white. 



C. SUleata, WESTERN SHELL-BARK H. From Penn. W. & S. : differs 

 from the foregoing in lighter-colored heart-wood, 7-9 leaflets more downy be- 

 neath, fruit with very thick husk 4-ribbed above the middle, and larger yellow- 

 ish or dull- white nut (sometimes 2' long) mostly with a point at both ends. 



C. tomentbsa, MOCKER-NUT or WHITE-HEART H. Common E. & S. : 

 bark rough, but not splitting off in strips ; shoots and lower surface of the 

 leaves woolly-downy when young ; leaflets 7-9, lance-obovate, or the lower 

 lance-oblong ; fruit with very thick hard husk, and globular nut (not flattish on 

 the sides) brownish, very thick-shelled, hardly fit to eat. 



* # Nuts bitter, in a rather thin and friable husk, which splits only at the top, or 



tardily to near the base : bark on the trunk close : bud-scales falling early. 



C. porcina, BROWN H. or PIG-NUT. Common N. : bark of trunk 

 rough ; bud-scales about 10, small ; shoots and leaves nearly smooth ; leaflets 

 5-7, obovate-lanceolate ; fruit pear-shaped; nut oblong or oval, hard-shelled, 

 seed at first sweet, then bitterish. 



C. amara, BITTER-NUT. Moist or low grounds : bark of trunk smooth and 

 very close ; yellowish bud-scales about 6 ; shoots and leaves pubescent when 

 young; leaflets 7-11, lanceolate or lance-oblong; fruit and white thin-shelled 

 and tender nut globular ; seed at first sweet, then very bitter. 



C. aquatic a, WATER H. River-swamps S. Small tree, with rough 

 bark ; bud-scales as in the last ; leaflets 9 - 13, lanceolate, smooth ; nut thin- 

 shelled, 4-angular, flattish ; seed very bitter. 



106. CUPULIFERSJ, OAK FAMILY. 



Trees or shrubs, with alternate and simple straight-veined leaves, 

 very deciduous stipules, and monoecious flowers ; the sterile in 

 slender catkins (except in the Beech) ; the fertile solitary, clustered, 

 or sometimes spiked, and furnished with an involucre which forms 

 a cup or covering to the 1-celled 1 -seeded nut. This nut comes 

 from an ovary with 2 or more cells having one or two ovules hang- 

 ing from the summit of each ; but all except one cell and one 

 ovule are abortive. There is a calyx adhering to the ovary, as is 

 shown by the minute teeth crowning its summit. Seed filled by 

 the embryo, which has thick and fleshy cotyledons. 



