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iiatelj, the venules being again branched, and the veinlets
anastomosing more or less near the margin. The sori are
borne along the sides of the venules in a very irregular
manner, the majority of them being directed towards the
apex of the pinna; at first the sori are quite concealed by
the scales, but the spore-cases ultimately protrude between
them, although, being very similar in colour, the latter are
never very obvious.
The Ceterach is a mural species, occurring on the walls
of old buildings and ruins, and in rocky places. It is
pretty generally distributed in the United Kingdom, but is
considered somewhat rare in Scotland. It occurs also
throughout central and southern Europe, and in the north
of Africa.
liike other wall Eerns, this is often difficult to establish
in cultivation when first transplanted; but when once this
is overcome its cultivation is not difficult. It is best grown
in a cold frame, potted rather high, among loam mixed with
a large proportion of brick-rubbish, and not over-watered.
Thougli generally found in exposed and rather sunny situations,
the finest examples we have seen were found in a
shaded, moist situation, under trees, where sunshine never
visited them.
Among other names, this plant has borne those of Asplénium
Ceterach, Scolopendrium Ceterach, Grammiiis Ceterach,
Notolepeum Ceterach, and Gymnogramma Ceterach.
Genus VI. CYSTOPTEKIS, Bernhardi.
The species of Cystopteris are all small, fragile Perns, yet,
notwithstanding, they are very beautiful and very interesting,
and furnish some remarkable differences of form. They are
much more delicate and herbaceous in their texture than the
majority of our native species, and hence are well adapted
for the purpose of minute investigation into the nature of
their venation and fructification. Their texture alone almost
suffices to tell a practised eye their family position, but the
tyro needs a more precise characteristic, and this is found in
the structure of the scale or indusium which covers the son.
The sori in these plants are round, as in Lastrea and Boly-
stiehum, all, equally with Cystopteris, once included under
the old family name of Aspidium; but here, instead of being
almost flat and circular, the indusium is inflated or bulged
out like a hood, and is attached at the back (towards the
base of the pinnule) of the sori by its broad base, covering
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