P.KAUTIFUL FERNS. 
27 
still narrower, and perhaps a little longer yet. Successive 
pinnae are gradually narrower, and less triangular in outline. 
At about the fifth pair they begin to grow shorter as well 
as narrower, and so rapidly decrease towards the acute and 
slightly acuminate apex of the frond. The secondary rachises 
arc very narrowly winged. The pinnules arc oblong or 
oblong-ovate, sub-acute, and set on rather obliquely. They 
are usually incisely lobed, but sometimes more deeply cut, 
into oblong lobes which are spinulosely toothed at the apex, 
and often somewhat so on the sides also. The veins are 
always free. There are a midvein and from five to seven 
veins in each lobe, the first vein being always on the supe- 
rior side. These veins arc either simple, or they bear a single 
short veinlet on the upper side half-way between the midvein 
and the margin. The sori are seated astride on the middle' 
of the vein, if it be truly simple, but if it be bent at an 
angle as if trying to branch, the sorus is directed towards the 
course the branch would take: — if the branch be actually 
formed, the sorus is seated on it, either near the apex or 
some distance below it according to the length of the branch. 
I do not find any good distinction between this variety and 
the next in the position of the sori, as indicated by Mr. 
Davenport. The lower surface of the frond is smooth and 
without glands, as is also the indusium, though most Euro- 
pean authors note more or less frequently occurring excep- 
tions to this rule. The spores are slightly reniform, and 
minutely verrucose. 
