BALSAM FIRS. 161 



mercial importance. It is obtained by puncturing the vescicles 

 (blisters) formed under the bark of the stem and branches 

 which contain from a few drops to a half teasponful each. 

 This is used in the arts and medicinally in chronic bronchial 

 and catarrhal affections. The smaller branches exhale a 

 delightful odor and are preferred by campers in the woods 

 for beds. 



Abies concolor. White Fir. Silver Fir. 



Leaves mostly obtuse, pale green, 1 to 2| inches long, 

 with two resin ducts close to the epidermis of the lower sur- 

 face. Cones oblong, cylindrical, 3 to 5 inches long, 1 to If 

 inches in diameter, pale green or sometimes dull purple. A 



large tree. 



Distribution. From Arizona to Southern Colorado, Utah 



and California. 



Propagation . By seeds . 



Properties of wood. Very light, soft, coarse grained, com- 

 pact, not strong; color very light brown or nearly white with 

 somewhat darker sapwood. Specific gravity 0.3638: weight of 

 a cubic foot 22.67 pounds. 



Uses. The White Fir is justly gaining in popularity as 

 an ornamental evergreen. When young it often spreads out 

 on the ground and seems slow to make an upward growth, but 

 after a few years it takes on a good broad conical form. Its 

 rather long leaves of a pale green color, and its light bark 

 and good form give it a very pretty appearance. It has stood 

 for more than ten years on the grounds of the Minnesota 

 Experiment Station without serious injury and has 

 made pretty specimens about six feet high and nearly as 

 broad. It undoubtedly prefers a moist soil, though it has 

 done very well on good retentive upland. The wood is of 

 very little value, but is used within its range for cheap pack- 

 ing cases, etc. 



Genus THUJA. 



Flowers mostly monoecious, on different branches in small 

 terminal catkins, opening in May; anther cells 2 to 4. Scales 

 of the pistillate flowers 8 to 12. Ovules 2 to 4. Fruit an erect, 

 dry, loose cone from one-third to one-half of an inch long, 



