105 



for food. The most valuable and edible nuts are obtained from the 

 Shag-bark Hickory (Carya ovata). 



This genus comprises about 10 species found in eastern North 

 America and 1, species in Mexico. Six species are native to this 

 State. One species, the small-fruited Hickory (Carya microcarpa, 

 Nutt. ) , sometimes considered a variety of the Pignut Hickory, is found 

 locally in the State but not described in this publication. In addi- 

 tion to our native species the Pecan Hickory (Oarya illinoensis) is 

 planted extensively for ornamental purposes and for the sweet nuts 

 which it produces. 



SUMMER KEY TO THE SPECIES. 



Page. 



1. Leaflets 7-11, small, lanceolate, usually curved C. cordiformis 110 



1. Leaflets 5-7, larger, broader than lanceolate, rarely curved, 2 



2. Husk of fniit splits tardily into 4 valves; valves of fruit tUin and rather friable at 



maturity; twigs smooth, relatively slender, cherry-colored to gray, C. glabra 109 



2. Husk of fruit splits promptly into 4 valves; valves of fruit thick and hard at 



maturity; twigs often hairy towards tip, rather stout, buff, gray, or brownish, 3 



3. Bark closo, rough but not shaggy on old trunks; twigs relatively stout; foliage scurfy 



or pubescent C. alba 108 



3. Bark .-shaggy separating into long idates on old ti'imks; twigs not so stout; foliage 



smooth or sometimes downy beneath, 4 



4. Leaflets usually 7; nuts dull white or yellowioh and pointed at both ends, C. laciniosa 107 

 4. Leaflets usually 5; nuts white, rounded or notched at the base C. ovata 106 



WINTER KEY TO THE SPECIES. 



1. Buds yellow with 4-6 bud-scales valvate in pairs: lateral buds often evidently- 

 stalked; terminal buds elongated and flattened, C. cordiformis 110 



1. Buds not yellow, truly scaly; bud-scales 10 or more usually overlapping, except outer 



ones on lateral buds which may form a closed sue but in time split from the 

 top; inner scales hairy, 2 



2. Buds small; terminal buds 1/5 to 2/5 of an incli long, their outer scales glandular 



dotted; twigs smooth, relatively slender, cherry-colored to gray; husk of fruit 



thin, not freely splitting to base, with thin-shelled nut, C. glabra 109 



2. Buds large; terminal buds 2/5 to 3/5 of an inch long, their outer scales almost 



glandless; twigs often hairy towards tip, rather stout, buff, gray, or brownish; 

 husk of fruit thick, freely splitting to base, 3 



3. Twigs relatively stout; bark rough and close, not shaggy; nut brownish, thick- 



shelled, with small kernel; terminal buds broadly-ovate with their outer scales 



early deciduous, C. alba 108 



3. Twigs not so stout; bark shaggy; nut white, dull-white, or yellowish with large 



kernel; terminal buds elongate-ovate with their outer scales tardily deciduous, 4 



4. Nuts dull white or yellowish and pointed at both ends, C. laciniosa 107 



4. Nuts white, rounded or notched at the base C. ovata 106 



I 



