BEAUTIFUL FERNS. 57 
base of the stalk, which, at the base of the lamina, are united 
into one of a horse-shoe shape by an arc parallel to the back of 
the stalk.” In the middle of a stalk from one of the California 
specimens I find two systems of ducts, one on each side of the 
stalk, and the two united by a curved and contorted border of 
firm blackish tissue (sclerenchyma). 
The fronds are from one to two feet long, and from three 
to six inches wide. In general shape they are oblong-lanceolate, 
acuminate, and slightly narrowed at the base. The texture is 
softly membranaceous, and both surfaces are smooth. The 
primary pinnae are numerous, the lower ones gradually farther 
apart : their shape is lanceolate from a broad base. They are 
usually twice pinnatifid, the pinnules being connected by a very 
narrow foliaceous border along the midribs. The ultimate seg- 
ments are sharply toothed. The fruit-dots are very abundant, 
and usually are found on all the pinnae. They are placed on 
the back of the free veinlets, and are apparently devoid of indu- 
sium ; though Dr. Mettenius has discovered on young fronds an 
exceedingly delicate and fugitive indusium, resembling in some 
degree that of A spieniwn% Athyrium. Accordingly, in his later 
work, he referred the species to the genus A spleniuni, placing it 
next to A. Filix-foemhia. Milde, in his work on the ferns of 
Europe and Atlantis, sought to re-establish Athyrhmi as a 
genus, and placed this fern in it, saying “ sori . . . rotundi, 
primurn breviter oblongi indusio fugaci minutissimo ciliato 
instructi.” The spores are ovoid, and apparently covered with 
anastomosing raised lines. Those I have examined are fus- 
cous-brown, but Milde says “sub-nigrae verrucosae.” 
