A preliminary List of the Ferns of Rolla, Missouri 
F. C. GREENE 
Rolla is situated near the center of the Missouri por- 
tion of the Ozark region. The surrounding district is 
rather rough and is consequently well drained, marshy 
Jand being almost unknown. The divides are capped 
by the Jefferson City formation, consisting of cotton 
rock above and pitted dolomite below. Underlying 
this is the Roubidoux sandstone which forms low cliffs 
along the streams. The lowest formation is the Gas- 
conade with its cliff-forming dolomite. Near the Gas- 
conade River this formation produces some fairly high 
and steep bluffs. 
The ferns found, as may be judged from the above 
statements, are chiefly rock-loving species. Further 
search will doubtless reveal some lowland species and 
the dry Gasconade cliffs should add several to the list. 
The most interesting find to date is Ophioglossum 
Engelmanni. On June 20, the writer found, in a hollow 
one mile west of Rolla, several thousand plants of this 
species, many of which were in fruit; on some plants 
the spikes had turned brown and on others had not yet 
attained the length of the leaf. Fertile plants three or 
four to eight inches long were found. The pitted 
dolomite mentioned above here forms a low cliff, back 
of which, away from the branch, is a small bench carved 
from the cotton rock. On this bench, for about one 
mile down the hollow—the distance examined—the 
adder’s tongue was very abundant among the rocks, 
growing in a dry, sterile soil. A few plants were found 
in the narrow bottom near the stream where the rock 
ledge dips below the water. 
Onoclea sensibilis. One colony of this species was 
found growing on sandstone in the bed of a creek. 
105 
