KEY, BASED UPON FLOWERS. 



h. Samara, 1-celled and winged all round (Ulmus). 



i. Flowers nearly sessile; samara not ciliate- fringed; leaves very 



rough above 11. U. FULVA. 



i 2 . Flowers on drooping pedicels; samara ciliate-fringed; leaves 

 smooth. 



Bud-scales glabrous ; flowers fascicled ; branches not corky. 



winged 33. U. AMERICANA. 



Bud-scales do wny-ciliate ; flowers racemed; branches corky- 

 winged 34. U. RACEMOSA. 



ft 2 . Capsule, dry, nut-like, not winged (Planera). 



114. P. AQUATICA. 



g z . Anthers introrse ; fruit a dark-purple drupe ; leaves long-taper- 

 pointed 12. CELTIS OCCIDENTALS. 



gr 4 . Anthers laterally dehiscent ; fruit a drupe. 



111. FORESTIERA ACUMINATA. 



C 2 . Flowers diclinous and one or both sorts in catkins. 

 d. Only one sort (the staminate flowers) in catkins. 



e. Fertile flowers single or clustered ; fruit naked ; leaves pinnately com- 

 pound (Juglandacece). 



f. Corolla present in the fertile flowers ; fruit with valveless epicarp 

 (Juglans). 



g. Fruit ovate, oblong and viscid-hairy 14. J . CINEREA. 



(/ 2 . Fruit globose, roughly dotted (not viscid-hairy) 35. J. NIQRA. 



/*. Corolla not present in the fertile flower ; fruit with usually 4-valved 



epicarp (Carya) which is 

 g. Thick ; valves separating to base ; bark 

 h. In loose plates, leaflets 



5, smoothish ; nut small 36. C. ALBA. 



7-9; nut large 64. C. SULCATA. 



h 2 . Close, leaflets 7-9, tomentose 90. C. TOMENTOSA. 



gr 2 . Thin ; bark close ; nut 



h. Quite smooth, small, thin-shelled, leaflets 



5-7; kernel edible 91. C. MICROCARPA. 



7-9; kernel very bitter 37. C. AMARA. 



h?. More ridged, larger, thicker-shelled ; leaflets 5-9. 



65. C. PORCINA. 



h 3 . Rugose, angular ; leaflets 11-13 115. C. AQUATICA. 



e*. Fertile flowers 1-3 together, invested wholly or partly with an involucral 



covering; leaves simple (Cupuliferce). 

 f. Involucre valveless, cup -like, composed of many scales and only partly 



inclosing the one nut, i. e., acorn (Quercus). 

 ff t Leaves with teeth and lobes obtuse or rounded (not bristle pointed); 



acorns maturing first year (and hence on now wood) and leaves 

 h. Oblong, sinuate-pinnatifid, nut immersed in the tubercled cup. 



38. Q. ALBA. 

 ft 2 . Lyrate-pinnatifid, nut \ or more immersed. 



Peduncles shorter than petioles 39. Q. MACROCARPA. 



Peduncles longer than petioles 66. Q. BICOLOR. 



ft 3 . Obovate and deeply sinuate-lobed, the two lobes near the summit 

 much the largest 93. Q. OBTUSILOBA, 



