24 BULLETIN 272, U. S. DEPARTMENT OF AGRICULTURE. 
sometimes remarkably wide, buttressed or ridged base. Toward 
maturity this form at the base gradually disappears as a result of 
change in growth toward a cylindrical or columnar form. Another 
cause is geological in character. The remaining basal swell becomes 
buried during the course of several centuries by alluvial and peaty 
deposits, often to a depth of from 3 to 5 feet. In swamps not sub- 
ject to high floods cypress usually has only slight basal swell (fig. 4). 
The narrowly pyramidal and symmetrical crown of smaller branches 
during earlier life gives way gradually during the second and third 
centuries to a broad, flat-topped crown consisting of a few wide- 
spreading, heavy limbs. This form persists during from two to four 
centuries; then decay, accompanied by winds, usually carries away 
considerable of the original top (Pl. IIT). In the open, cypress 
maintains a full crown of many small branches more cylindrical in 
form and very much less dense than the eastern red cedar. 
_ BARK. 
The bark shows extreme variation from a thick, deeply furrowed 
fibrous bark to a thin scaly one. The tree is very responsive to 
physical environment. In Florida, for example, near fresh, deep 
water, the bark at all ages is very thin, soft-fibered, and light brown 
in color, while in adjacent situations with sluggish or stagnant water 
the bark is thick and of a reddish color, the heartwood is darker and 
somewhat heavier, and the sapwood thinner and more uniform in 
width (Pl. X). In the great Wilmington Swamp of North Carolina 
the bark is prevailingly thick and firm. During logging it breaks 
apart into long, stringy fibers of a rich brownish-red color. The 
difference in bark thickness ranges mostly from 4 to 14 inches. All 
intermediate gradations are present, and when the two extremes 
appear in the same region they are accompanied by different condi- 
tions of soil and moisture. 
LEAVES. 
The foliage consists of very small flat or needle-shaped leaves, . 
_ arranged either in two ranks or closely appressed to fragile branchlets. 
Cypress is a conifer, but not an evergreen tree, and both leaves and 
branchlets are dropped in the fall. The wide variation in leaf form 
appears to be accompanied by corresponding differences in the 
amount and acidity of the water supply. 
ROOT SYSTEM. 
The conical base of cypress divides below the surface into about 
six to ten strong descending and spreading roots, which provide a 
deep anchorage for the tree. The form suggests that of a mush- 
room anchor. In addition to the descending roots, a number of 
large laterals extend outward near the surface like cables and form 
