Fig. 32.-- Cypress swamp in the Cache River bottom- 
land. The ‘'knees’’ that grow up to 7 feet tall tend to sur- 
round the bald cypress trees. This picture was taken during 
the dry season. 
extends from Belknap eastward to the Ohio River. 
(A view of the Cache River is shown on the cover.) 
In preglacial times, it was not the Cache but an ex- 
tension of the present Cumberland River that flowed 
through this valley; the Cache was then a tributary 
that entered the larger valley where it does now, that 
is, between Belknap and Forman, Johnson County. 
After glaciation, the Cumberland emptied into the 
Ohio; the Cache followed the preglacial valley of the 
the Cumberland and flowed westward and southward 
to empty sometimes into the Ohio and sometimes into 
the Mississippi. In this valley are numerous remnants 
of cypress swamps, two of which are especially note- 
worthy for both plants and animals. 
Two and one-half miles west and 1 mile north of 
Karnak is a sizable remnant of a cypress swamp. It 
occupies parts of sections 7 and 8, T. 14S., R. 2 E., 
in Johnson and Pulaski counties. The river here 
serves as the county line. Illinois highway 37, which 
carries much traffic from Chicago to Cairo, traverses 
this swamp from north to south. The Cache River here 
occupies a part of the preglacial Cumberland valley. 
During much of the year the ground is inundated, 
often by as much as 6 feet of water, but frequently in 
the dry season -- late summer and early autumn -- the 
water recedes and it is possible to walk in the 
swamp. The large trees of this swamp are bald cy- 
press and tupelo, both of which have buttressed 
bases. Many of the bald cypresses are surrounded by 
pneumatophores or knees, fig. 32, that grow up to 
7 feet high. Other trees of this swamp are overcup 
oak, swamp cottonwood, Mississippi hackberry, river 
birch, Drummond’s maple, swamp honey locust, and 
water elm. The last is limited in Illinois to a few of 
the cypress swamps. 
24 
Common shrubs in the Karnak swamp include 
swamp privet, buttonbush, and, less frequently but 
still locally abundant, Virginia willow. Trumpet creep- 
er is a very abundant vine in this swamp; Brunnichia 
cirrhosa grows along the border. 
The floor of the swamp near the border supports 
a growth of herbaceous plants, including lizard’s-tail, 
false nettle, a rare milkweed named Asclepias 
perennis, and clearweed. Deep in the swamp the floor 
is mostly devoid of vegetation except for seedlings 
of some trees. On decaying logs that float when water 
is present or rest on the swamp floor in the dry sea- 
son are found peculiar plant associations that have 
such species as clearweed, Virginia willow, beggar- 
ticks, the small composite known as Eclipta alba, 
and marsh St. John’s-wort crowded together. 
The large number of sizable bald cypress trees 
in this swamp is of interest to botanists. Some indi- 
vidual trees are 3.5—4.0 feet in diameter above the 
buttressed bases. Several specimens measure 5.0— 
5.5 feet in diameter and up to 100 feet tall. Also of 
interest to botanists is the polypody found growing as 
an epiphyte on a single ash tree. 
Another cypress swamp remnant in the Cache 
River valley is a mile north and one-half mile east of 
Belknap or slightly more than a mile southwest of 
Forman in Johnson County. It is located in the north- 
east quarter of section 36, T. 13 S., R. 2 E., and 
occupies about 100 acres. This is in the preglacial 
Cache River valley and is near the point where the 
Cache enters the larger valley of the preglacial Cum- 
berland. The area of biological interest embraces not 
only the cypress swamp but also the forested bluff to 
the south of the swamp; at the base of the bluff is a 
spring. 
The forest trees of the bluff include hard maple, 
black walnut, hickories, sweet gum, mulberry, and 
papaw. Poison ivy is the most abundant shrub under 
the forest canopy, but wild hydrangea and spicebush 
Fig. 33.-- A decaying log on the floor of a Cache Riv- 
er cypress swamp. An interesting association of plants 
grows on such logs, which are afloat during wet seasons and 
grounded during dry periods. 
