10 AMERICAN FERN JOURNAL 
soil species. The writer has not had the opportunity 
to study the Venus’ hair fern, A. Capillus-Veneris, in the 
field, but descriptions of its habitats indicate that it 
falls into the same class. 
The Christmas fern, Polystichum acrostichoides, is 
about as nearly indifferent to soil reaction as a plant 
can be. It grows alike in the mediacid sands of the 
Coastal Plain, in decaying wood in the Dismal Swamp, 
in leaf mold, and in the alkaline soils over limestone 
ledges. The most luxuriant plants, however, appear in 
the soils of intermediate reactions. Braun’s Holly fern, 
P. Braunii, seems to be rather more limited in its soil 
preference. It has been studied in the vicinity of Lake 
Willoughby, Vermont, and at its southernmost known 
station in Ganoga Glen, Luzerne County, Pennsylvania. 
In the former region the rocks are decidedly calcareous, 
and the soils neutral or slightly alkaline; in the latter 
locality the rock is a red sandstone, and the soils slightly 
acid. The plant thus falls into the circumneutral soil 
class. 
The narrow-leaved spleenwort, Athyrium angustifol- 
tum (formerly classed as an Asplenum; also known as 
A. pycnocarpon) is most common in limestone regions, 
in practically neutral or somewhat alkaline soils. In 
Virginia just northwest of the District of Columbia it 
grows in neutral river sand, but also extends up the 
bank into soils of slightly acid reaction. On the whole, 
however, its relations suggest it to be a circumneutral 
soil species. The related silvery spleenwort, Athyrium 
acrostichoides (also formerly an Asplenium; once A. 
thelypteroides) is decidedly more wide-ranging, thriving 
in subacid soils as well as in minimalkaline ones; it is 
accordingly classed as indifferent. 
The lady-fern group (Asplenium Filix-Foemina of old) 
has now been subdivided into two species, Athyriwm 
asplenioides and A. angustum, which may perhaps be 
