52 WILD FLOWERS AND TREES OF COLORADO 



2a. Foliage leaves (needles) in bundles of two or more surrounded at base by a short 

 sheath. Leaves mostly more than 25 mm. (1 in.) long. Cones hard and woody 

 when mature. Genus 1. Pinus 



2b. Foliage leaves (needles) solitary, not in bundles; mostly less than 25 mm. (1 in.) 

 in length. Mature cones leathery or papery; not hard and woody. (3) 



3a. Leaves jointed near the base, the lower part of the leaf brown and woody and remain- 

 ing on the branchlet after the rest of the leaf has fallen. Leaves in our species stiff 

 and four-angled, not flat. Cones pendulous. Genus 2. Picea 



Fig. 45. — Leaves of Coniferous Trees, i. Pine (Pinus); 2. Douglas Spruce 

 (Pseudotsuga); 3. Spruce (Picea); 4. Fir (Abies). 



3b. Leaves not brown nor woody at base, flat. When they fall off they leave a scar but 

 no part of the leaf remains. (4) 



4a.' Leaves rather soft; narrowed toward the base into a short stalk which broadens 

 slightly at the point of attachment. Leaf-scars transversely elliptical. Cones 

 pendulous, the projecting bracts three-pointed. Genus 3. Pseudotsuga 



4b. Leaves somewhat stiff, very slightly narrowed at base; leaf scars rather large, cir- 

 cular in outline. Cones erect, dark purple or blackish or sometimes yellow. 



Genus 4. Abies 



KEY II. FOR IDENTIFICATION OF DECIDUOUS TREES 



1 a. Leaves simple; not composed of leaflets. 

 ib. Leaves compound; of three or more leaflets. 



(2) 



