Botany in Colorado 25 



PINUS THE PINES 



Key to the Species 



1. Leaves 5 in each sheath. 



1) Cones 2.0-2.5 in. long, tips of scales blunt, each with central 

 prickle. 



Foxtail Pine-P. aristata 



2) Cones 3.0-5.5 in. long, tips of scales rounded, without prickles. 



Limber Pine-P. flexihs 



2. Leaves 2-3 in. each sheath. 



1) Leaves 3-6 in long, cones large with many scales. 



Bull Pine-P. ponderosa 



2) Leaves not more than 3 in. long. 



1 Cones very hard, with many scales, remaining long closed, 

 seeds small. 



Lodgepole Pine-P. murrayana 



2 Cones resinous, with few scales, soon opening exposing the very 

 large wingless seeds. 



Pinon Pine-P. edulis 



PICEA THE SPRUCES 



1. Leaves very stiff and sharp pointed; surface of twigs between the leaves 



smooth, i. e. not hairy; cones 2-4 in. long. 



Blue Spruce-P. parryana 



2. Leaves not so stiff and not sharp pointed; surface of twigs between the 



leaves covered with fine hairs; cones 1-2 in. long. 



Englemann Spruce-P. engelmanni 



PSEUDOTSUGA DOUGLAS FIR 



One species, P. taxifolia, with the characters indicated in the generic key 

 above. 



ABIES THE FIRS OR BALSAMS 



1. Leaves on vigorous shoots 1-2 in. long, the two resin passages near the 



center of the leaf; cones 1-2 in. long, at maturity purple or almost 

 black. 



Sub-alpine Fir-A. lasiocarva 



2. Leaves on vigorous shoots 2-3 in. long, the two resin passages near the 



lower surface; cones 2-4 in. long at maturity yellow or purple. 



White Fir-A. concolor 



JUNIPERUS THE JUNIPER 



Leaves in 3's, awl-shaped, rigid, free and jointed at the base, spreading; 

 fruit sub-globose, bright blue, covered with a glaucous bloom. 



Low Juniper-J. commums 



SABINA- 



1. Leaves minutely notched at the apex; berry 0.12-0.25 in. long, usually 



with a single seed. 



One-seeded Sabina-$. monosperma 



2. Leaves entire at the apex; berry somewhat larger, usually with more than 



one seed. 



Western Sabina-S. scopulorum 



