THE BROAD BUCKLER FERN 
315 
and is thickened at its juncture with the rootstock. 
Stipes and rack is are channelled along their upper side 
and smooth behind. The leafy portion of the frond is ex- 
tremely beautiful, not only on account of its numerous 
divisions and indentations, but from the circumstance that 
the edges of the lobes of the pinnules are beautifully in- 
dented and bent back, or curled under. The fronds have a 
very elegant appearance when unrolling, because of their 
greatly divided form, and the rolled-in leafy heads have often 
a peculiarly dusky or dark-brown appearance owing to the 
dark colouring of the scales. The general outline of the frond 
is broadly lance-shaped or ovate, almost triangular, from the 
fact that it is usually broadest at the base and tapers upwards 
to a point at its apex. It is tri-pinnate, or three times divided 
at the base of the frond, and bi-pinnate higher up. The 
pinnae are set on the rachis generally opposite in pairs. The 
lowest pair is much the broadest, the second pair is the 
next broadest, and succeeding pairs become narrower and 
narrower as they become shorter, until they are merged 
into an elongated point at the apex. The pinnae are divided 
into pinnules, alternately placed along on opposite sides of 
their mid-stems, the pinnules being again divided either 
quite down to their mid-stems Or in a pinnatifid manner 
into beautifully serrated lobes. The lowest pair of pinnae on 
the frond are the most divided, and it is especially noticeable 
that the pinnules below the mid-stems on this pair are much 
longer than those above them. The difference in length is 
very prominent in the basal pinnules next the main rachis. 
But it becomes less and less prominent in succeeding pairs, 
until near the apices of the pinnae the pinnules above and 
below the mid-stems are of the same length, and being- 
much smaller and narrower are also much less divided, being 
ultimately only notched or serrated, and not divided into 
lobes. In the second pair of pinnae next above the basal 
u 
