KEY, BASED UPON LEAVES. 13 



/*. 7, leaflets, sessile 105. MELIA AZEDARACH. 



e' 2 . Regularly bipinnate except for the lowest pair of single leaflets ; 



leaflets stalked 27. GYMNOCLADUS CANABENSIS. 



e 3 . Irregularly bipinnate, leaflets small and sessile, 



12-18 in number 109. GLEDITSCHIA MONOSPERMA. 



18-24 in number 27. GLEDITSCHIA TRIACANTHOS. 



d 2 . Quickly falling away and petioles developing into phyllodia 



155. ACACIA MELANOXYLON. 

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



8. ARALIA SPINOSA. 

 rt 2 . Subdeciduous Leaves a part only of the leaves falling in autumn, the rest 



remaining green through the winter. 

 Obovate-spatulate, entire, shining green both sides. 



118. QUERCUS AQUATICA. 



3 . Persistent Leaves evergreen. 

 b. Simple 



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

 (I. In fascicles \Pinus) of 



e. Two each, a membranous sheath inclosing the base of each fascicle, 

 about 



/. 1 in. long, sheaths very short 99. P. BANKSIANA. 



/ 2 . lf-2* in. long and 



Stout; sheaths i in. or less; branchlets smooth and purple 



98. P. INOPS. 



Slender i in. or more; branchlets rough -scaly 148. P. CONTORTA. 



f*. 2-3 in. long, slender, with short sheaths 122. P. CLAUSA. 



f 4 . 3-5 in. long, 

 g. Slender; branchlets 



Rough 75. P. MITIS. 



Smooth 123. P. GLABRA. 



/. Thicker; cones in whorls and very oblique 170. P. MURICATA. 

 5-6 in. long, thicker, sheaths elongated 19. P. RESINOSA. 



e". Three each and 

 /. 3-6 in. long; cones 



H-3 in. long, little if at all oblique 50. P. RIGIDA. 



3-5 in. long, very oblique 1 99. P. RADIATA 



/*. 5-8 in. long 121. P. SEROTINA. 



/ 3 . 7-10 in. long, very stout 147. P. PONDEROSA. 



/ 4 . 8-15 in. long; cones 



Subterminal, slightly if at all oblique 124. P. PALUSTRIS. 



Lateral, very oblique and heavy 



4-8 in. long; leaves slender, pale blue-green 198. P. SABINIANA. 



10-14 in. long; leaves stout, dark green 169. P. COULTERI. 



e 3 . Both two and three each 125. P. CUBENSIS. 



e 4 . Five each, 

 3-5 in long 



Very slender; cones 4-6 in. long 49. P. STROBUS. 



Rather stout, cones 10-18 inches long 146. P. LAMBERTIANA. 



9-13 in. long; cone-scales thickened at apex and furnished with strong 



prickle 197. P. TORREYANA. 



(I*. Not in fascicles (scattered) 

 e. Ridged above and below and base 

 /. Elevated and persistent 

 </. 4-sided; branchlets 



Pubescent 20. PICEA NIGRA. 



Glabrous.. 100. PICEA ALBA. 



<y 2 . Flat; branchlets smooth; cones cylindrical 149. PICEA SITCHENSIS. 



/ 2 . Not elevated nor persistent ; leaves short thick and crowded. 



174. ABIES MAGNIFICA. 



e 2 . Terete 196. PINUS MONOPHYLLA. 



c. Linear, flat and 

 (I. Conspicuously 2-ranked (diverging in two directions), 



