26 



BULLETIN 55, U. S. DEPAETMEISTT OF AGEICULTUEE. 



soils lacking an abundance of moisture, and. often become points of 

 entrance for destructive gi'ound rot. The strongly developed lateral 

 roots extend horizontally m all du'ections 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. •!. — Leaf structure of AbUs hshcarpa: D, ducts; B, Inmdle sheath; F, fibro-vascular bundle; M 

 mesophyll; 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 



