Sor, Reactions or FERNS 9 
was found to characterize a swamp in the mountains 
north of Slatedale, Pennsylvania, where it was dis- 
covered, far from its usual Coastal Plain surroundings, 
by Mr. Harold W. Pretz. Experiments in the writer’s 
garden have shown it to be readily killed by applica- 
tions of calcareous (Potomac river) water. It is evi- 
dently an intensely-acid soil species. The broad-leaved 
chain fern, Woodwardia virginica (sometimes placed in 
the genus Anchistea) thrives best in mediacid sphagnum 
swamps and bogs, being in fact a pernicious weed in the 
cranberry bogs of southern New Jersey. It tolerates 
a decidedly lower degree of acidity than does the pre- 
ceding species, however, having been observed in waters 
of as low as minimacid reaction in glacial drift near 
Allentown, Pennsylvania (Pretz), in the New Jersey 
Marl area and in the region around Cape Henry, Vir- 
ginia. It is accordingly classed as merely an acid soil 
The common brake, Pteridium latiusculum (Pteris 
aquilina of old) grows in great abundance in the New 
Jersey Pine Barrens and elséwhere in the Coastal Plain 
sands, and might be supposed to be an intensely-acid 
soil plant. Its root system lies at a considerable dis- 
tance beneath the surface, however, and is often sur- 
rounded by material of only moderately acid reaction. 
It seems quite definitely to avoid limestone, although 
in the vicinity of St. Johnsbury, Vermont, it has been 
observed to grow in calcareous glacial drift, of but minim- 
acid reaction. It has also been found in the District 
of Columbia in red clay soils of this low acidity, and is 
to be classed as tolerant of all degrees of acidity. 
The maiden-hair fern, Adiantum pedatum, thrives 
best where leaf mold of cireumneutral reaction accumul- 
ates, and grows also in soils containing limestone frag- 
ments, exhibiting slight alkalinity. It appears to avoid 
the more acid soils, and is classed as a circumneutral 
