EVERGREENS OF COLORADO 



23 



specimens are now 

 grown in the nur- 

 series of Holland. 

 Roster's blue 

 spruce is a partic- 

 ularly fine form 

 with strongly sil- 

 vered foliage ob- 

 tained by selection 

 from among a 

 large number of 

 seedlings. This 

 form of the blue 

 spruce is propa- 

 gated by grafting 

 upon the seedlings 

 of the ordinary 

 type. The blue 

 spruce is well 

 adapted to the for- 

 mation of hedges 

 and wind breaks 

 and when used for 

 the former pur- 

 pose, it makes a 

 practically impas- 

 sable hedge even 

 for smaller ani- 

 mals on account 

 of the stiff, ex- 

 tremely sharp 

 needles. The blue 

 spruce is at its 

 Fig-. 12. Lodg-epole pine. a. Needles, two in each best onlv w h p n 



bundle, x2. b. Cross- section of needle, xlO. c. Mature, 



open cone. d. Closed or "tight" cone. e. Seeds, x 1. grown in a moist, 



fertile soil and in full sunlight. When clothed in the new growth, some 

 of the well developed trees have the appearance of being frosted \yith 

 pale blue, at which season they are unexcelled in beauty among evergreen 

 trees. 



2. THE ENGELMANN SPRUCE. 

 Picca cngelmnnni (Parry) Engelm. 



This tree has a general range from the mountains of British Columbia 

 southward through the interior mountain ranges of the continent to 

 Northern New Mexico and Arizona. It reaches its greatest size and 

 beauty in the northern part of its range. In Colorado, it is the most 

 abundant of the true spruces and forms extensive forests on the upper 



