10 KEY, BASED UPON LEAVES. 



/ 3 . 7-9, epicarp thick and woody, leaflets. 



Puberulent, bark shaggy 64. CARYA SULCATA. 



Tomentose and oderous 90. CARYA TOMENTOSA. 



/*. 7-11, lanceolate, acute at base, minutely glandular and pubescent 



beneath 37. C. AMARA. 



Oblong-lanceolate, glabrous, obtuse or rounded at base : fruit a 



samara, flat at base 62. FRAXINUS SAMBUCIFOLIA. 



6 3 . Decompound Leaves. 



c. Petioles smooth and leaves 



Regularly bipinnate excepting for the lowest pair of single leaflets ; 



leaflets* stalked 27. GYMNOCLADUS CANADEJXSIS. 



Irregularly bipinnate, leaflets small and sessile. 



28. GLEDITSCHIA TRIACANTHOS. 



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



8. ARALIA SPINOSA. 



cC 1 . Leaves Evergreen remaining on over winter. 

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

 C. In fascicles of 



d. Two each, a membraneous sheath, inclosing the base of each fascicle 1 in. 



or thereabouts in length, sheaths short 99. PINUS BANKSIANA. 



l|-2i in. long sheaths short ; branchlets purple 98. PINAS INOPS. 



3-5 in. long, slender, sheaths elongated 75. PINUS MITIS. 



5-6 in. long, quicker, sheaths elongated 19. PINUS RESINOSA. 



flP. Three each, sheath short 56. PINUS RIGIDA. 



d 3 . Five each, sheath deciduous 49. PINUS STROBUS. 



C 2 . Not in fascicles (scattered) short, 4-angled and usually more or less curved ; 

 branchlets. 



Pubescent ; leaflets rather thick 20. PICEA NIGRA.* 



Smooth, leaflets slender 100. PlCEA ALBA. 



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. 



6 3 . Scale-like or awl-shaped. 



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

 flat and two-edged branchlet 24. THUJA OCCIDENT ALIS. 



c 2 . Scale-like, smaller, appressed in four ranks and making a rather 4-angled 

 than flat branchlet ; fruit a 



Small spherical cone 74. CHAMAECYPARIS THYOIDES. 



Bluish berry 25. JUNIPERUS VIRGINIANA. 



* Abies nigra in text. 



