88 Christmas Fern 
primary branch of the pinna’s midvein. This auricle some- 
times, in very highly developed leaves, actually becomes a pin- 
nule, as will be seen further on. The lower basal sides of the 
pinne mostly remain more or less oblique to the rachis. 
The early leaves are crenately toothed or lobed, but one or 
more spinulose or at least apiculate lobes are usually to be seen 
before the first pair of pinne becomes distinct. More spinulose 
points appear in subsequent leaves, until the blunt teeth or lobes 
are almost or quite superseded. Each spinulose point occurs 
at the apex of a veinlet of the leaf, but one is not present at the 
apex of every veinlet. In the later leaves there is usually one or 
more to every primary branch of the pinne’s midveins. 
The leaf becomes fertile first above and the fertile pinne 
are contracted. 
In some plants, some or all of the leaves become very highly 
developed, with the following results. In the fertile leaves the 
soriferous zone extends downward, forming a sort of triangle, 
the pinne, like the leaf-blade itself, becoming soriferous first 
at the apex, and their soriferous parts mostly becoming con- 
tracted. Incisions occur between the primary branches of the 
pinne’s midveins and sometimes deepen sufficiently to render 
the leaf subbipinnate. These primary branches, constituting 
the midveins of the pinne’s segments, are more complex than 
in the usual pinne. 
The so-called ‘vars. 
Gray, are based on these highly developed leaves. These leaves 
re a ts 
schweinitzii” Beck, and ‘‘incisum ” 
are usually very large and densely soriferous, and, as Mr. A. A. 
Eaton has pointed out, appear to be the product of extreme 
luxuriance of the plant. From the following facts and from my 
* See Fern Bulletin, 8: 13. 1899. 
