KEY, BASED UPON LEAVES. 5 



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



samara, flat at base 62. FRAXINUS SAMBUCIFOLIA. 



/. 3-5, subentire 77. PTELEA TRIFOLIATA. 



ft 3 . Decompound Leaves. 

 c. Petioles smooth or pubescent; pinnnae 

 d. Remaining on during the season; leaves 

 e. Regularly bipinnate; pinnae 

 /. 2, leaflets. 



g. 4-6, 2-3 lines long, petiole, -J in 128. CERCIDIUM TORREYANUM 



g 2 . 8-13, 1-2 lines long, petiole almost or quite wanting. 



204. PARKINSONIA MICROPHYLLA. 

 g 3 . 10-30, petiole 



JL-* inches lono- 205. PROSOPIS ODORATA. 



2-4 inches long . 129. PROSOPSIS JULIFLOKA 



f 2 . 7, leaflets, sessile 105. MELIA AZEDARACH. 



/ 3 . 8-15, numerous, 1-4 lines long 



Rather distant 206. ACACIA DECURRENS. 



Crowded 227. ACACIA MOLLISSIMA. 



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



leaflets stalked 27. GYMNOCLADUS CANADENSIS. 



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. 

 a*. Subieciduous 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. 



a 3 Persistent Leaves evergreen. 

 b. Simple 



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

 d. 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 . H-2^ in. long and 



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



98. P. INOPS. 



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



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



/. 3-5 in. long, 

 g. Slender; branchlets 



Rough 75. P. MITIS. 



Smooth. 123. P. GLABRA. 



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

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



c 2 . Three each and 

 /. 3-6 in. long; cones 



Little if at all oblique 1^-3 in. long 50. P. RIGID A. 



Very oblique and scales mammillate on outer side. 



Ovoid scales furnished with minute prickles 50. P. RADIATA. 



Cylindrical ovoid, prickles stouter 222. P. ATTENUATA. 



f 9 . 5-8 in. long : 121. P. SEROTINA. 



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



/ 4 . 8-15 in. long; cones 



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



gr 2 . 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. 



c 8 . Both two and three each 125. P. CUBENSIS. 



e*. Four each (occasionally five) 245. P. QUADRIFOLIA. 



