Som. Reactions oF CERTAIN FERNsS—I 21 
_ ete. The literature shows similar relations to exist in 
other regions. Tests have shown circumneutral reac- 
tions to be present in most cases, however, and in excep- 
tional ones where the soil is low in calcium compounds 
and subacid in reaction, the plant is stunted and plainly 
not thriving. Pellaea glabella, which is recorded in the 
literature only on limestone, has been studied at two 
localities near Allentown, Pennsylvania, to which the 
writer was kindly guided by Mr. Harold W. Pretz. The 
soil in both places being made up of dolomitic limestone 
fragments, the reactions naturally proved to be more or 
less alkaline. Both species of Pellaea are thus to be re- 
garded as typical calcareous soil plants, with, in the for- 
mer case, a moderate tolerance for acid reactions. 
Cryptogramma Stelleri (Pellaea gracilis) has been re- 
corded most frequently on limestone, but also occasion- 
ally on sandstone, slate, and gneiss rocks. In Vermont 
it was found to be definitely limited to calcareous 
gneiss, the soils being more or less alkaline; but at Lin- 
coln Falls, Sullivan County, Pennsylvania, a locality 
brought to the writer’s attention by Dr. Everett G. 
Logue, of Williamsport, it grows in wet crumbly red 
sandstone. Such rocks sometimes yield strongly acid 
soils, but in this case tests of the soil into which the 
fern’s roots extended showed the reaction to be neutral 
or at most slightly acid. The usual classification of this 
species as a calcareous soil plant practically intolerant 
of acid is therefore believed to be correct. 
The writer has not had the opportunity to study Phyl- 
litis Scolopendrium (Scolopendrium vulgare) in the field, 
but its soil reaction seemed to be of so much interest that 
tests were made on the soils of herbarium specimens, 
kindly furnished by Mr. Maxon. As the latter has 
pointed out in describing the distribution of this fern in 
America,‘ it grows in Tennessee in a stiff clay, forming a 
‘Fernwort Papers, 30-46, 1900. 
