JUGLANDACEAE. 95 



Leaflets 7-0 : nuts pointed at both ends. 3. H. lacinioaa. 



Leaflets 3-5 : nuts rounded or notched at the base. 4. H. ovata. 

 Middle lobe of the staminate calyx usually about equal to 

 the lateral : husk of the fruit not freely splitting to 

 the base. 

 Bark shaggy : fruit mostly subglobose : nut thin-shelled : 



seed sweet. 5. H. microcarpa. 



Bark close : fruit mostly obovoid : nut thick-shelled : 



seed bitter. 6. H. glabra. 



1. H. cordiformis (Wang.) Britton. Tree becoming 30 m. tall, the close bark 

 with shallow furrows and flat ridges : leaflets 5-9 ; blades of the lateral ones 

 lanceolate or oblong-lanceolate, 8-15 cm. long, falcate : staminate aments slender, 

 7-13 cm. long: fruits subglobose, 2.5-3 cm. long, slightly 6-ridged, the thin 

 husk tardily 4-valved : nut smooth, thin-walled, the seed bitter. Common, in 

 low grounds. BITTER-NUT. SWAMP-HICKORY. 



2. H. alba (L.) Britton. Tree becoming 30 m. tall, the bark with flat ridges: 

 leaflets 7-9; blades of the lateral ones oblong to oblong-lanceolate, 8-15 cm. 

 long: staminate aments stout, 10-15 cm. long: fruits globose-obovoid, 4-6 cm. 

 in diameter, the husk very thick : nut angled, thick-shelled, the seed sweet. 

 Common, in woods. MOCKER-NUT. WHITE-HEART HICKORY. 



3. H. laciniosa (Michx.) Sarg. Tree becoming 40 m. tall, the bark separating 

 in narrow plates: leaflets 7-9, or rarely 5; blades of the lateral ones oblong or 

 oblong-lanceolate, 10-20 cm. long: staminate aments stoutish, 9-20 cm. long: 

 fruits broadly oblong or oblong-obovoid, 5-8 cm. long, the husk very thick: nut 

 broadly oblong, thick-shelled, the seed sweet. M. Bare, along the Conestoga 

 Creek, near Lancaster. (Not recently collected.) Limestones. KING-NUT. 



4. H. ovata (Mill.) Britton. Tree becoming 40 m. tall, the bark separating in 

 large plates: leaflets 5, or rarely 7; blades of the lateral ones oval to oblong- 

 lanceolate, 10-15 cm. long: staminate aments stout, 6-12 em. long: fruits sub- 

 globose, 3-5 cm. thick, the husk thick; nut slightly angled, thin-shelled, the 

 seed sweet. Not very common, except along the river, and creeks. SHELL- 

 BARK. SHAG-BARK HICKORY. 



5. H. microcarpa (Nutt.) Britton. Tree becoming 25 m. tall, the bark sep- 

 arating in thin plates: leaflets 5-7; blades of the lateral ones oval, oblong, or 

 ovate-lanceolate, 6-14 cm. long: staminate aments slender, 7-14 cm. long: fruits 

 subglobose, 2-2.5 cm. thick, the husk thin: nut barely angled, thin-shelled, the 

 seed sweet. Common, in woods. 



6. H. glabra (Mill.) Britton. Tree becoming 60 m. tall, the close bark in flat 

 ridges: leaflets mostly 3-7, the blades of the lateral ones oblong or oblong- 

 lanceolate, 7-15 cm. long, acuminate, green beneath, glabrous: staminate 

 aments 6-10 cm. long: fruits subglobose, obovoid or pyriform, 3.5-5 cm. long: 

 the husk thinnish : nut angled, thick-shelled, the seed astringent. N. M. 

 Common, in woods. Sandstones and shales, limestones. PIG-NUT. 



Order FAGALES. 



Shrubs or trees. Leaves alternate: blades simple. Flowers monoe- 

 cious or rarely dioecious, at least the staminate borne in aments, the pis- 

 tillate sometimes with an involucre which becomes a bur or cup in fruit. 

 Calyx usually present. Corolla wanting. Fruit a nut or rarely a samara. 



Staminate and pistillate flowers in aments : fruit never with a bur or cup. 



Staminate flowers solitary in the axil of each bract, without a calyx: pistillate 



flowers with a calyx. Fam. 1. COBYLACEAE. 



Staminate flowers 2-3 together in the axil of each bract, 



each with a calyx : pistillate flowers without a calyx. Fam. 2. BETULACEAE. 

 Staminate flowers in aments : pistillate often solitary, the 



involucre becoming a bur or cup. Fam. 3. FAGACEAE. 



