KEY TO THE SPECIES OF SPRUCES 



Cone scales rounded at tip, smooth or wavy (erose) on margin. 

 2. Cones under 2 inches long; needles 4-sided; eastern or north- 

 western. 



3. Cones Vi-Wi inches long, ovoid, purple, persistent many 

 years; scales stiff, rigid, brittle, with wavy margins; twigs 

 hairy; needles blunt-pointed; transcontinental and northern 



P. mariana, Black Spruce, p. 53. 



3. Cones VA-2 inches long, oblong, brown, falling in 1 year; 

 scales smooth on margin or nearly so; needles pointed. 

 4. Cone scales stiff and rigid at maturity ; twigs more or less 



hairy; eastern United States and Canada 



P. rubens, Red Spruce, p. 55. 



4. Cone scales soft and flexible at maturity ; twigs not hairy ; 



transcontinental and northern 



P. glauca, White Spruce, p. 51 . 



2. Cones 2-4 inches long; scales with entire margins; needles 



flattened ; alpine in California and Oregon 



P. breweriana, Brewer Spruce, p. 59. 



Cone scales wedge-shaped at tip, margin wavy (erose). 



5. Cones 4—7 inches long; drooping foliage; needles 4-sided, not 



prickly ; common European ornamental 



P. abies, Norway Spruce, p. 48. 



5. Cones rarely 4 inches long ; native and western. 



6. Needles flattened, not prickly, yellow-green; cone 2Vi-4 



inches long; Pacific Coast airea 



P. sitchensis, Sitka Spruce, p. 59. 



6. Needles 4-sided, blue-green ; western mountain region. 



7. Cone 1-2 Vi inches long, persistent 1 year; needles 

 flexible, acute but not prickly to touch; twigs minutely 

 hairy; buds V&-I4 inch long with scales usually ap- 



pressed; bairk on mature trees thin and scaly 



P. engelmanii, Engelmann Spruce, p. 57. 



7. Cone 2V4-4V^ inches (mostly about 3i/i inches) long, 

 persistent 2 years; needles stiff, bristle-pointed; twigs 

 glabrous; buds V^-Vi inch long with scales usually re- 

 flexed, bark on mature trees thick and furrowed; central 

 Rocky Mountains P. pungens, Blue Spruce, p. 61. 



[49] 



