THE MOUNTAIN PARSLEY FERN. 101 
Fronds from four to twelve inches high, including the stipes, 
herbaceous, of a lively green, terminal on the caudex, triangular 
or ovate-triangular in outline, of two forms, and hence described 
as dimorphous. Sterile fronds leafy, usually about as long as the 
stipes, bi- or tri-pinnate, smooth. Pinne alternate or sub-opposite, 
triangular-ovate, spreading, the lower ones largest. Pinnules alter- 
nate, ovate, largest on the lower side of the pinne, pinnate or 
pinnatifid, the pinnulets or lobes ovate, or obovate-cuneate ; the 
latter or smaller ones, cut into linear acute teeth, and the former 
into cuneate-linear bifid lobules, having acute incurved teeth. The 
ultimate divisions are, however, variable in form, being sometimes 
oblong-oval, with sinuously shallow-toothed margins, this form of 
development apparently representing fertile fronds, whose fructi- 
ferous growth has become arrested and abortive. Fertile fronds . 
contracted, usually about one half as long as their stipes, tripin- 
nate or in some cases quadripinnate in the basal portions of the 
lower pinne. Pinne alternate or sub-opposite, ovate, spreading, 
the lower ones largest. Pinmules alternate, ovate in outline, bipin- 
nate or pinnato-pinnatifid in the lower pinne, pinnate only above. 
All the ultimate divisions are stalked, obtuse, and linear-oblong 
from the involution of the margins, which are pale-coloured, 
crenated, and indusioid. 
Venation of the barren fronds consisting of a slender costa extending 
along each pinnule, and casting off a vein into each of its lobes or 
pinnulets, this again becoming alternately branched, so that a venule 
or veinlet runs along the centre nearly to the point of each segment 
—simple where the segment is undivided, and forked where it is 
bifid, one branch being directed towards every marginal tooth. 
In the fertile fronds a costa or midvein enters each ultimate divi- 
sion, and passes in a sinuous course to its apex, throwing out 
alternate veins which extend nearly to the margin, and are usually 
simple but sometimes forked and bear a sorus near to their 
extremity. 
Fructification on the back of the frond, and usually occupying 
the whole under surface. Sori small, roundish, situated near the 
extremity of the venules; at first distinct though contiguous, ulti- 
mately becoming laterally confluent and forming a continuous line. 

