26 
BULLETIN 55, U. S. DEPARTMENT OF AGRICULTURE. 
soils lacking an abundance of moisture, and, often become points of 
entrance for destructive ground rot. The strongly developed lateral 
roots extend horizontally in all directions for a distance of 4 or 5 feet, 
and even more. The bark of the roots is bright red and comes off in 
thin scales. 
FLOWERS. 
The female and male flowers (cones) occur on the same tree in the 
top at the outermost ramifications of the branches. The female 
flowers occupy the extreme top near the ends of the upper branches 
and are borne perpendicularly in the leaf axils on the upper sides of 
Fig. 4.— Leaf structure of Abies lasiocarpa: D, ducts; B, bundle sheath; F, fibro- vascular bundle; M 
niesophyll; E, epidermis; S, strengthening cells. 
the previous year's branches, while the male flowers are borne mostly 
on the under or lower sides. The cones, which are violet in color, 
cylindrical shaped, and from 2 to 4 inches long, do not turn downward 
after fertilization, like the cones of spruce, but remain erect. They 
ripen in one year, about the end of September. The mere opening 
of the erect cones does not liberate the seeds, but the flat, smooth 
scales of the cone and the scale bracts themselves drop off, carrying 
the seed with them, and leaving the axils of the cone on the tree for 
years. The deciduous scales of the cone are broad, round at the top, 
and narrow to a wedge at the bottom. Within each scale are two 
