I:VI-:I:C,KI-:I-:XS OF COI.OILXDO 



little stalks remain on the branches for several years after the green 

 portion of the needle has fallen off. This gives the branchlets a very 

 rough appearance after the needles have fallen, which readily serves to 

 distinguish the spruces from the firs. In our species, the needles are 

 four-angled in cross section and end in sharp pointed tips. The pistillate 

 tiower cones are produced at the ends of small lateral branches. They 

 are usually somewhat larger than in the pines and are dark brownish 

 purple. The staminate flower cones, instead of being crowded together 



in dense masses around 

 the new growth, are scat- 

 tered along the branchlets 

 and are usually somewhat 

 larger and looser than 

 those of the pines. The 

 seed-bearing cones of the 

 spruces require but one 

 season in which to mature 

 their seeds. During the 

 blossoming period t h e y 

 point upward, but after 

 being pollinated and fer- 

 tilized, the cones become 

 pendulous or hanging and 

 remain in this position as 

 long as they are attached 

 to the tree. In some cases, 

 as in the E n g e 1 m a n n 

 spruce, the cones may be 

 borne in sue h crowded 

 clusters that some of them 

 are forced to point up- 

 ward. They usually open 

 in late autumn or early 



I'ino. Douse growth fol- 

 lowing ;i lores? tiro. winter tor the discharge 



of the seeds. The seeds are much smaller than in any of the pines and 

 each one is furnished with a long thin wing. The spruces occur mostly 

 in moist soil, either along streams and gulches or on the northern and 

 eastern mountain slopes. They furnish some of our most ornamental 

 evergreen trees and are useful in the formation of hedges, wind breaks 

 and shelter belts. There are but two species of spruces native to the 

 mountains of Colorado. 



KEY TO THE SPECIES OF PICEA IN COLORADO 



I. Needles very stiff and sharp pointed; surface of the twig among the 



needles of the new growth smooth and free from fine hairs; mature 

 cones L' to '.', inches long. 1. /'/;<, i>an-i/<i>t<t. 



II. Needles less rigid and sharply pointed; surface of the twig among 



the needles of the new growth finely pubescent or hairy; cones 1 to 

 2 inches long. 2 . I'icca Enwlmanni. 



