168 
ASPIDIACE^. 
drying without considerable difficulty. The lateral veins are 
alternate and generally three-branched, the anterior branch 
usually terminating half way between the mid-vein and margin, 
the others reaching the margin, but being quite free at their ex- 
tremity. It should, however, be observed, that the auricle or lobe 
at the base of each pinna has a formula of venation decidedly 
different from the remainder of the pinnule, since the principal 
vein in this lobe emits several fruitful branches in an opposite 
direction to that taken by the rest. The involucre is circular, 
and attaclied to the back of each anterior branch of the lateral 
veins near its extremity ; the attachment is by a short central 
cord : the capsules are attached to the vein around the base of 
the cord of the involucre, and, as they reach maturity, form a 
circular cluster, and these clusters a continuous line on each 
side of the pinna, about equidistant from its midrib and margin. 
Some specimens are so densely seeded that the masses become 
confluent. In the Irish, as in all other specimens, the clusters 
of capsules are most abundant towards the apex of the frond, 
but they are also scattered throughout the other parts, even to its 
base, whereas in the Scotch, Welch, and particularly the English 
specimens, the masses are confined to the upper part of the 
frond. Mr. Tatham, in allusion to these observations, remarks 
that in the Settle plant “ the seed is generally confined to about 
a third of the frond, but I have some that are half covered.” 
The fronds represented at page 163 are from Scotland; those 
at page 166 from Wales : figure h shows the venation, and the 
points whence the clusters of capsules have been removed ; 
figure c represents a pinna with the fructification in a very young 
state, the peltate involucre alone being visible ; figure d another 
pinna, in which the clusters of capsules have swollen, and more 
or less concealed the involucre : the figures at page 167 are 
from an Irish plant. 
