OAK FAMILY. 301 



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

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

 fruit spherical. ' ' 



* « PlarUedfrom the Old World: hush friable, separating when dry from the 



rovndish and smoothish thin-shdkd nut. 

 J. rfegia, English Walnut, so called, but native of Asia : leaflets oval 

 entire, smoothish ; fruit ripens sparingly in Middle States. 



^\t^4^^-^! hickory. (Greek name of the Walnut, applied to these 

 JNorth Amencan trees.) Fl. in rather late spring : nuts fall in autumn. 

 § 1. Sterile catkins in a sessile cluster : lea/lets 13-15, short-stalked: nut edible. 

 C. oliV8Bf6rmis, Pecan-nut. 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: leaflets sessile er 

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



* Nuts sweet-tasted and edible (the hickory-nuts of the marka) ; the husk splitting 



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



C. ^ba, Shell-bark or Shag-Bahk H. Commonest E. : bark of old 

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

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

 and lance-obovate ; nut white. 



C. SUlcdita, 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. toment6sa, Mockek-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 Utter, 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. porclna, 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-Ianceolate ; fruit pear-shaped; nut oblong or oval, hard-shelled, 

 seed at first sweet, then bitterish. 



C. am^a, Bitter-nut. Moist or low grounds : bark of trunk smooth and 

 very close ; yellowish bud-scales about 6 ; Sioots 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. aqu&tica. Water H. Rivei^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. CUPULIPERJS, 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. 



