6 KEY, BASED UPON LEAVES. 



e' 1 . Leaflets 7-9, ovate or lance-oblong entire or obscurely serrate. 



Petioles and branchlets glabrous 10. FKAXINUS AMEKICANA. 



Petioles and branchlets velvety pubescent. .31. FRAXINUS PUBESCENS. 

 d?. Leaflets sessile or subsessile. 



e. Numerous (15-17) and pubescent, especially along the petioles and rachis. 

 f. Leaflets ovate-lanceolate, finely serrate; pubescence of short rust colored 

 clamy hairs. 



Fruit subovoid, viscid-pubescent 14. JUGLANS CINEREA. 



Fruit globose, roughly dotted (not viscid-pubescent). 



35. JUGLANS NIGRA. 

 / 2 . Leaflets lance-oblong, coarsely serrate; pubescence of copious, longer 



and whiter hairs 5. RHUS TYPHINA. 



e 2 . Seven to 11 leaflets, the terminal subsessile 37. CARYA AMAKA. 



e 3 . Five leaflets, the terminal petiolulate 36. CARYA ALBA. 



ft 3 . Decompound Leaves. 

 C. Petioles smooth and 



Leaves regularly bipinnate excepting for the lowest pair of single leaflets; 



leaflets stalked 27. GYMNOCLADUS CANADENSIS. 



Leaves irregularly bipinnate, leaflets small and sessile. 



28. GLEDITSCHIA TRIACANTHOS. 

 C 2 . Petioles prickly, leaves large with ovate, sessile, serrate leaflets. 



8. ARALIA SPINOSA. 



tt 2 . Leaves Evergreen remaining on over winter. 

 ft. Needle-shaped and quite stiff, pointing every way. 

 c. Long, 1 in. or more, in fascicles of 



Two each, a broad membranous sheath enclosing the base of each 



fascicle 19. PINUS RESINOSA. 



Three each, sheath short 50. PINUS RIGIDA. 



Five each, sheath deciduous 49. PINUS STROBUS. 



c 2 . Short, 8 lines or less, scattered (not in fascicles), 4-angled, usually more or 



less curved 20. ABIES NIGRA. 



6 2 . Linear, small, flat and diverging in two directions. 



C. Petioled, obscurely denticulate, 8 lines or less in length. 



21. ABIES CANADENSIS. 



c 2 . Sessile, entire, 8 lines or more in length 22. ABIES BALSAMEA.. 



ft 3 . Scale-li^e or awl- shaped. 



c. Imbricated and closely appressed in four ranks, but making a conspicuously 



flat and two-edged branchlet 24. THUJA OCCIDENTALS. 



C 2 . Scale-like leaves smaller, appressed in four ranks and making a rather 

 4-angled than flat branchlet. Awl -shaped leaves arranged in whorls of 

 three each. . . . 35. JUNIPERUS VIRGINIANA. 



