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THE SHIELD FERNS. 
POLYSTICHUM. 
have here a genus of ferns, the European members of which, taken as a 
whole, are sufficiently distinct from any other group, although it is not 
always easy to discriminate them from each other. It is often the case 
that plants which are generically very distinct and easily recognisable are 
extremely close in their specific relations ; and, as we shall see later on, it 
is certainly so in the present instance. The genus Polystichum contains 
about fifty species, all of which have all the veins of the pinnules free ; 
its peculiar characteristics, according to Mr. Moore, “consist in the puncti- 
form sori being dorsal in the free veins, and covered by circular peltate 
indusia.” They are almost all of them characterised by their rigid texture, 
which gives them a very distinct appearance : and, in the European species, 
by the spiny teeth with which the pinnules are bordered. They are distributed throughout 
the world, both in the tropical and temperate regions. None of them seem to call for any 
particular remark, unless perhaps P. munitum , a North American species, which deserves 
notice on account of its economic properties. The North American traveller, David Douglas, 
tells us that the fronds of this species are used as garlands by the Indians, and that the 
rhizomes form an article of food among them, being cooked and eaten. The name Polystichum 
signifies many-ordered, and was given in allusion to the numerous rows of sori which are 
regularly distributed over the fronds. 
THE HOLLY FERN: POLYSTICHUM LONCHITIS, Roth. 
This is one of our rarer British ferns, and one which is very liable to be falsely 
recorded, on account of the resemblance which a variety of P. aculeatum, known as 
P. lobatum, bears to it. It is, indeed, a trap for the unwary youthful botanist, and one 
which, in our younger days, we admit having been extremely near falling into, the superficial 
likeness between it and the true Holly Fern being very great. Those who have not seen the 
true Lonchitis are to be excused for such a mistake ; the likeness when lobatum and Lonchitis 
are placed side by side is, however, not very striking. A knowledge of the distribution of 
the Holly Fern in England may assist in preventing mistakes ; it is quite a northern plant, 
its most southern locality being in West Yorkshire and Carnarvonshire: it has been recorded 
for Glamorgan, but doubtfully. Of course this by no means implies that the species will 
certainly not occur farther south, but there is a very strong antecedent probability that any 
fern suggesting P. Lonchitis at the first glance will prove on investigation to be one of 
the forms of P. aculeatum. In Carnarvonshire it occurs in several localities, as on Snowdon 
and on Glyder Vawr, above Llanberis, and near Twll-du, “ the Devil’s Kitchen,” but in 
almost inaccessible places. Durham and Westmoreland, with Yorkshire, already mentioned. 
