THE BROAD PRICKLY-TOOTHED BUCKLER FERN. 227 
scaly, especially at the back, with small subulate more or less dis- 
tinctly two-coloured scales. 
Fronds averaging two to three feet, but (exclusive of the varieties 
noticed below) varying from about a foot to five or six feet in 
length, and from six to sixteen inches in breadth, herbaceous, dark- 
green above, paler beneath, spreading, and more or less arched or 
drooping, ovate or ovate-lanceolate in the typical form, bipinnate 
or tripinnate. Pinne numerous, opposite or sub-opposite, the pairs 
more distant below. The lowest pair are obliquely-triangular 
elongate, the posterior pinnules being much larger than, often twice 
as large as, the anterior ones; the pinne of a few of the succeeding 
pairs have also an obliquely-deltoid outline, the obliquity gradually 
disappearing towards the upper part of the frond, so that those of 
about the third or fourth pair, as well as those above them, are nearly 
equal-sided: the upper pinne are also narrower, tapering very gra- 
dually from the base to the apex. Pinnules ovate-oblong, acutish, 
often convex, the basal ones stalked, the upper sessile and decurrent ; 
the lower ones (especially those of the lowest pinn®) are very 
deeply pinnatifid, sometimes pinnate, and the lobes or pinnulets 
are oblong and bluntish in outline. All the divisions are sharply- 
toothed, with teeth of subovate form, terminating in a bristle-like 
point or mucro, which is in general curved laterally towards the 
apex of the pinnule or lobe. 
Venation in the pinnulets of the lower pinne, consisting of a 
stout flexuous vein, proceeding from the costa or rachis-like vein of 
the primary pinnule, forming a midvein, from which à venule pro- 
ceeds into each marginal lobe, and this is forked where the lobe is 
toothed, so as to give off a branch towards each tooth, the anterior 
branch being fertile at some distance below its apex. In the 
larger of the less divided primary pinnules, the same arrangement - 
occurs on a reduced scale, the costa producing a vein for each lobe, 
and this again a venule for each tooth, the lowest anterior venule 
only being fertile. The same arrangement, still more simplified, 
occurs in the smaller primary pinnules. The venules all terminate 
in a small club-shaped apex, below the tooth towards which they 
are directed. 
Fructification on the back of the frond, and occupying the whole 
Q 2 

