KEY, BASED UPON FLOWERS. 



h. Samara terete at base; leaflets petiolulate 



New growth smooth 10. F. AMERICANA. 



New growth pubsecent 31. F. PUBESCENS. 



/t 2 . Samara broad at base 62. F. SAMBUCIFOLIA. 



/ 2 . Ovules single in each of the 1 or 2 cells of the ovary. 



gp. Anthers opening by uplifted valves ; stigma single and entire 

 (Lauracece) flowers 



Perfect ; calyx persistent ; leaves evergreen ( Persea) . 



113. P. CAROLINENSIS. 

 Dioecious, calyx deciduous, leaves deciduous ; involucre none 



(Sassafras) 32. 8. OFFICINALE. 



gF 2 . Anthers extrorse ; stigma 2-cleft ; fruit a 



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. 



h?. Capsule, dry, nut-like, not winged (Planera). 



114. P. AQUATICA. 



gr 3 . 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. 

 & Only one sort (the stamiuate 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. 



gr 2 . Fruit globose, roughly dotted (not viscid-hairy) 35. J. NIGRA. 



/ 2 . Corolla not present in the fertile flower ; fruit with usually 4-valved 



epicarp (Carya) which is 

 gr. 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. 



71 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. 



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



65. C. PORCINA. 



71 3 . Rugose, angular ; leaflets 11-13 115. C. AQUATICA. 



e 9 . Fertile flowers 1-3 together, invested wholly or partly with an involucral 



covering; leaves simple (Cupuliferce). 



