12 KEY, BASED UPON LEAVES. 



3 . 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. 



a?- Persistent Leaves evergreen. 



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

 c. In fascicles (Pinus) of 



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

 about 



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



e 2 . lf-3 in. long and 



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



98. P. INOPS. 

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



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



e 4 . 3-5 in. long, 

 f. Slender; branchlets 



Rough 75. P. MITIS. 



Smooth 123. P. GLABRA. 



/ 2 . Thicker; cones in whorls and very oblique 170. P. MURICATA. 



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



d?. Three each and 



e. 3-6 in. long 50. P. RIGIDA. 



e''. 5-8 in. long 121. P. SEROTINA. 



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



e*. 8-15 in. long; cones 



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



Lateral, very oblique and heavy. 169. P. COULTERI. 



d\ Both two and three each 125. P. CUBENSIS. 



d 4 Five each, 3-5 in long, sheath deciduous ; leaves 



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



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



c 2 . Not in fascicles (scattered), ridged above and below and base 

 d. Elevated and persistent 

 e. 4 sided; branchlets 



Pubescent ' 20. PICEA NIGRA. 



Glabrous 100. PICEA ALBA. 



e 2 . Flat; branchlets smooth; cones cylindrical. .149. PICEA STITCHENSIS. 

 d*. Not elevated nor persistent ; leaves short thick and crowded. 



174. ABIES MAGNIFICA. 

 6 2 . Linear, flat and 



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

 d. Petioled and margin 



Obscurely denticulate, 8 lines or less in length. .21. TSUGA CANADENSIS. 



Entire, revolute, -1 inch in length 144. TAXUS BREVIFOLIA. 



&. Subsessile rigid and sharply bristle-pointed, about 1 inch long and gen- 

 erally tapering from wide base. 120. TORREYA TAXIFOLIA. 



1-3 inches long, of more nearly uniform width. 



145. TORREYA CALIFORNICA. 

 d\ Sessile, entire, keeled below 

 e. Narrow linear, obtusely pointed 



| in. long or less 22 ABIES BALSAMEA. 



2-3 in. long 173. ABIES CONCOLOR. 



e 2 . Wide-linear, pungent at apex, in. long or less 



143. SEQUOIA SEMPERVIRENS. 

 c 2 . Somewhat-2-ranked, short- petiolate 

 d. Articulated on a permanent-base and keeled above 



171. TSUGA PATTONIANA. 



d 2 . Breaking away entire and leaving permanent leaf -scars 

 f to 1 in. long ; winter buds 5 j in. 



150. PSEUDOTSUGA TAXIFOLIA. 



f to 1 i in. long ; winter buds - in. 



PSEUDOTSUGA MACROCARPA. 

 b*. Scale-like or awl-shaped, imbricated and closely appressed 



