CONSPECTUS OF THE NORTH AMERICAN SPECIES. 



Apocahta. Bud-scales valvate ; catkins of staminate flowers usually from buds formed in the 

 axils of leaves of the previous year ; fruit ridged at the sutures ; nut subcylindrical, or in one 

 species much compressed and angled, the wall thin and brittle, or in one species thick and 

 bony ; lacunae usually large ; kernel sweet or bitter. 



Catkins of staminate flowers fascicled, nearly sessile, usually on branches of the previous 

 year. 



Leaflets 13 to 15, oblong-lanceolate, more or less falcate ; nut ovate-oblong ; cylin- 

 drical, thin-shelled ; kernel sweet 1. H. Pecan. 



Catkins of staminate flowers pedunculate from branches of the year or of the previous year. 

 Leaflets 7 to 11, lanceolate or oblong-lanceolate ; nut often broader than long, thin- 

 shelled, slightly 4-angled ; kernel bitter 2. H. minima. 



Leaflets 7 to 11, ovate-lanceolate to lanceolate-obovate ; nut ellipsoidal, cylindrical, 



thick-shelled ; kernel sweet 3. H. myristic^formis 



Leaflets 7 to 13, lanceolate, more or less falcate ; nut compressed, rugose, thin-shelled ; 



kernel bitter 4. H. AQUATICA. 



EucARTA. Bud-scales imbricated ; catkins of staminate flowers pedunculate on branches of the 

 year. Fruit without sutural ridges, or in one species slightly ridged ; walls of the nut thick 

 and bony ; lacunse minute ; kernel sweet. 



Bark separable from old trunks in long loose plates. 



Leaflets 5 to 7, ovate to oblong-lanceolate or obovate ; nut thick or thin-walled, ovate, 



more or less flattened and 4:-angled, pale or nearly white 5. H. ovata. 



Leaflets 5 to 9, obovate or oblong-lanceolate, puberulous on the lower surface ; nut 



ovate, thick-walled, prominently 4-angled, dull white to light reddish brown . . . 6. H. laciniosa. 

 Bark closely furrowed, rarely exfoliating in plate-like scales. 



Leaflets 7 to 9, oblong-lanceolate or obovate-lanceolate, more or less tomentose on the 

 lower surface, very fragrant ; nut globose or oblong, often long-pointed, 4-ridged 



toward the apex, thick-shelled, reddish-brown 7. H. ALBA. 



Leaflets usually 5 to 7, oblong or obovate-lanceolate, glabrous or villous-pubescent ; 

 fruit pyriform or globose ; husk usually thin, slightly ridged at the sutures ; nut 

 oblong, oval, or globose, thick or thin-shelled 8. H. glabra. 



