154 



maintained ; and it is with this object in view that the selection of the 

 first name given has been made. 



Information has been derived from an examination of herbarium and 

 other specimens, as well as from a free use of a large number of forestal 

 and botanical publications ; among them Gray's Manual, Watson's 

 Botany of California, Prof. C. S. Sargent's Forests of I^orth America, 

 Coulter's Manual of Eocky Mountain Botany, together with various 

 Government rex)orts and current botanical and forest literature. In- 

 formation has also been derived from the personal observations and 

 correspondence of Col. E. T. Ensign. 



ARTIFICIAL KEY TO GENERA AND SPECIES. 



I. Leaves without a true stem : 



Needle-shaped or scale-like Conifers. 



Sword-shaped, very long, thick, attached toau uuhrauched trunk.. Yuccas. 

 II. Leaves with a true stem and a more or less broad blade.. Broad--Leayed Trees. 

 III. Leaves none (anomalous) 49 



CONIFERS. 



Leaves in clusters: 



2, 3 (not regularly 4), or 5, with a delicate scaly sheath at the base : Pines: 

 Leaves 2 in a sheath : 



1 to 2 iuches long ; cones with blunt scales 5 



1 to 3 (mostly 2) iuches long ; cones with prickle-pointed scales 9 



Leaves 3 (sometimes 2) in a sheath : 



2i to 3^ inches long; cones with delicate prickles 8 



3 to 6 inches long ; cones with strong prickles 7 



Leaves 5 in a sheath : 



1 to li inches long ; cones with delicate prickles 6 



, .l^to 2^ inches long ; cones with blunt scales 3 



to 2 (exceptionally 2^ to 3) inches long 2 



2f to 4 inches long (often 4 in a sheath) ; seeds large, wingless 4 



3 to 4 inches long; seeds small, winged 1 



More than 5, proceeding from a bud: Larches : 



14 to 20 leaves in a cluster 20 



40 to 50 leaves in a cluster 21 



Leaves single: 



Bristling all around the branches ; more or less 4-sided and pointed : Spruces : 



Leaves very stiff, stout, and acutchj pointed > 12 



Leaves moderately stiff, rather slender, awl-pointed : 



Cones with margin of scales entire • 10 



Cones with margin of scales indented H 



Comb-like, or 2-rauked in arrangement on the branches, flat, blunt, notched, 



or pointed: 



Leaves rather thin, onslender hranches ; cones hanging, scales persistent : 



Hemlocks, etc. : 



With 3-pointed bracts protruding from under the scales 19 



With no bracts protruding from under the scales : 



Cones I to f of an inch long, downy 17 



Cones 2 to 3 inches long, not downy 18 



