THE LADY FERN AND ITS KIN, 187 
Fertile and sterile fronds are much alike and the 
former are sharply distinguished from those of other spe- 
cies by their regular rows of clear-cut. sori. Beginning 
at the base of each pinnule, these alternate on each side 
of the midvein almost to the tip. They are usually set 
close together and curve slightly outward at an 
oblique angle nearly to the edge of the pinnule in a very 
pleasing pattern. Occasionally the lower sori are double, 
opening away from each other, and on the long slender 
tips of the pinnz they are nearly always so. In heavily 
fruited fronds the fruit covers nearly all the under surface 
of the blade. The indusia are rather thick and for most 
of the summer retain the silvery white colour of their 
youth thus giving the common name to the plant. The 
fronds do not survive the frosts. 
This species is found from Canada and Minnesota to 
Alabama. It also occurs in Eastern Asia. It is con- 
sidered a fairly common species—never so common as 
the lady fern, perhaps, although often forming dense 
thickets in small areas. After studying it for many 
years, I am inclined to agree with the author of “ How 
to Know the Ferns” that “although it cannot be classed 
among the rare things, it is absent from many promising 
localities.” American authors frequently give this species 
the name of Asplentum acrostichoides. This is the older 
by three years, but has never been commonly accepted. 
The Narrow-Leaved Spleenwort. 
The rarest of the larger Asplenitums is without doubt 
the narrow-leaved spleenwort (A splentum angustifolium). 
According to Eaton, it has no very near relatives any- 
where. It is a true Asplenium and not an Athyrium, 
