THE COMMON PRICKLY SHIELD FERN 
P. aculeatum is very difficult to distinguish from its near ally Р. angulare, and yet, viewing the 
ugh every 
British forms, they appear to be distinct, Indeed, were it otherwise, a series varying thr 
gradation from pinnate to tripinnate must be united, and all hope of definin; 
a species would be at an end, 
While thus admitti 
ig the difficulty of diserim 
ig between some forms of these species, and without 
presuming to | 
y down any infallible rule for effecting t 
object, we may point out how they may with 
tolerable certainty be known from each other, presuming that in the applicati 
d appreciation of 
the distinguishing peculiarities some general knowledge of the plants is desirable P. aculeatum is 
® stouter, more erect, and altogether more rigid plant than P. angulare, which is normally lax and 
herbaceous, equally large or even larger in its size, 2. P. aculeatum has its pinnules either confluent 
or decurrent, in which cases there is no difficulty whatever in distinguishing it; or, when the pinnules 
are distinct, as in the most perfect plants, they are wedge-shaped at the base, the anterior side being 
truncate, and the posterior obliquely incised in str: 
ight lines, the two lines describing an acute angle hy 
the apex of which they are attached to the rachis, In P. angulare the truncated anterior base has a 
moro curved outline, and the two lines of the base des 
right angle or an obtuse angle, at the apex 
of which is a distinct slender petiole, by which they are attached. 3. P. aculeatum has 
that is, 
attached at а point along the middle part of the venule; it is in fact nearer the base of the 
venule, ie, the point of furcation, than the apex, which is carried out to the margin of the pinnule, In 
P. angulare the fertile venule stops about midway across the pinnuld, and the sorus is commonly placed 
at or almost close to its apex. These peculiarities observed in connection with each other will serv 
to reduce tho dubious forms within very narrow limits indeed, at least, so far as British examples 
are concerned. ‘The portion rather below the mi 
ldle of the frond should be taken for examination 
‘This is one of the most easily cultivated of all the larger hardy ferns. It prefers a loamy soil and 
Partial shade; and is increased readily by division. Being evergreen, its varieties are among the most 
de 
able of our native species for the decoration of shady walks and rockeries, in which latter situation 
especially, where the roots are generally well drained, provided the pl: 
effects of 
nts are not exposed to the 
ere drought and aro moderately shaded, they thrive admirably. It is also very manageable 
as a pot plant, and under any circumstances is ornamental in its character. ‘The smaller form, known 
as lobatum, is perhaps the most өш 
table for pot culture, on account of its size and the elegance of its 
fronds, which not uncommonly assume a very graceful lateral curve. 
The allied Р. Lonchitis, though a у 
vous looking and hardy plant in its native haunts, is seldom. 
seen to preserve its vigour under cultivation, at least in the neighbourhood of London, probably on 
account. of the impossibility of imitating the pure atmosphere of its native mountains. It certainly 
ut, its roots too should be 
prefers a damp atmosphere; and, provided the moisture is not sta; 
freely supplied ; they should 
fact be constantly moist with percolating moisture: and hence the 
necessity of a careful mechanic 
adjustment of the materials employed as compost, of which mellow 
m, gritty к 
nd, and small masses of some porous body, such as soft sandstone 
hould be the main 
edients. We have succoeded tolerably well by potting the pla 
ts very firmly in such a compost with 
x small proportion of peat added, the plants being kept under glass in a close cold shaded frame, but 
the removal of the plants for the winter to a cold greenhouse where the atmosphere was drier, led to 
the partial de 
of the fronds. The 
ame plants however on being enclosed within a hand 
where consequently the atmospheric moisture was more abundant and regular, gı 
ew vigorously : so 
that we have no doubt the requirements of this species are a well moistened but freely-drained soil and 
a damp atmosphere, which can only be secured in many cases by keeping the plants close under glass. 
ted by division, lateral crowns being seldom produced ; consequently, 
plants generally have to be obtained 
‘om their native habitats. As it fructifies freely, they might be 
raised from the spores 
"There are various di 
es of development in this species, some of the most distinet of which have 
