V. CY9TOPTERIS, 7o 
being deeply pinnatifid, their lobes resembling the up- 
per pinnules. The texture is very delicate: from this 
cause, the venation is distinctly seen. The mid-vein 
of each pinnule is more or less sinuous or flexuose ; 
from this the venules are produced alternately, becoming 
more or less branched. In the larger lobes, where the 
venule becomes a secondary midvein, a series of simple 
branches are usually produced, each extending to the mar- 
gin, and generally bearing a sorus towards its extremity ; 
in the smaller lobes the lateral veins become two, three, or 
four-branched, one branch extending to each of the serra- 
tures of the lobe. The son are usually numerous, one being 
borne by most of the veins ; they are disposed rather nearer 
the mid-vein, than the margin, and are at first distinct 
though they often become confluent afterwards and cover 
the whole under surface. They are of small size and nearly 
circular, covered by a pale membranous concave or hood- 
shaped indusium, which is attached by its broad base be- 
neath the capsules on the side towards the base of the lobe, 
the other extremity, or that towards the apex of the lobe, 
becoming free, and at this part usually split, jagged, or torn 
into narrow unequal often capillary segments. This in- 
dusium soon becomes reflected, and is at length obliterated, 
or pushed off by the growing spore cases. 
The variety anyustata is one of the larger forms of the 
species, growing from six to fifteen inches high. It differs 
from the commoner variety in the more ovate outline of 
the frond, which is much attenuated and lengthened at the 
apex ; in having its pinnse lanceolate with the point much 
narrowed and extended ; and in its pinnules being linear- 
lanceolate, deeply and acutely pinnatifid, or slightly 
toothed at the margin, the ultimate divisions being always 
oblong or linear and acute, never dilated rounded or ovate. 
The son too are smaller and less prominent, and always 
continue distinct, standing either solitary, or in pairs, to- 
wards the bottom of each lobe or tooth, and thus occupy- 
ing a sub-central position. This variety does not appear 
to be very common. 
