THE BRITTLE BLADDER FERN 
confined dampness generally maintained in structures where ferns are grown, but as we find native 
imens from Ben Lawers and from Ireland aro similarly affecte appear to be a natural 
wing ; which are, however, not always so well defined as could be wished 
(Smith). The form to which this name has 
1. ануша а given appen 
st the species, and includes those forms in which the edges of the smaller pinnules, and of the 
lobes of the larger ones, are deeply and rather evenly conspicuous longish narrow teeth. 
According to Sir J. E. Smith this is the same as the Polypodium rhæticum of Dickson and of Bolton 
inate. Mr. W 
(Bil, Brit. t. 45). The spores (in Dickson's plant) are roundish and ec llaston and 
others think it is not a v bly there are more than one to which the mame is 
stant form, and pro 
applied, some of which may revert under culture to the ordinary state; but we have a plant smaller 
indeed than Smith's description seems to point out, which we include under angustata, and this with 
us is quiet constant under cultivation, Tt is more attenuated in the frond, the pinnae, and the pinnules 
and these are its chief characteristics. 
(М), This is а distinct and constant form, cultivated by Mr, A. Tait, of Edinburgh, It is 
peculiar in its short blunt ovate narrowly tly stalked pinnules, which are deeply separated 
into distinet oblong lobes, almost pinnules, and these are notehed with small even teeth, which are very 
apparent, The spores are echinate. The colour of the fronds is a dark green, 
3. dentata (Dickson). There are some cultivated forms referable to this variety that aro constant, 
though it is probable that accidentally blunt pinnuled fronds of other forms aro sometimes associated 
with it in the herbarium, and hence it is often looked on as inconstant, The features of the true plants 
эге, small size (four to eight inches long), and confluent pinnules, so that the narrow fronds are sometimes 
scarcely bipinnate ; these pinnules are blunt-oblong, simply blunt-toothed, or obscurely blunt-lobed, and 
with the sori placed near their margi d forms, having the 
Somewhat larger and more 
ply 
same aspect, aro met with, and through these it gradually merges into obusa, and the normal form. 
The spores are ochinate, but searecly in so marke in C. fragilis 
4. decurrens (ML). А var 
ty intermediate in aspect between dentata and Dicki 
the latter in the decurront pinnules and deflexed pinne, but different in the moro acute apices of the 
fronds and pinnules, and in the more ereet and prominent teeth, which rather resemble tho f 
does the colour and texture, ‘The spores are echinnte. It was f 
und by Mr, Тай, on the coast 
of Fifeshire 
Dickieana: (Bim). The m. 
t marked in habit of all the known forms, but connected with fragilis, 
decurrens and dentata, and therefore only to be considered as а variety. Its peculiarities 
consist in the deflexed pinn more or less overlapping, and in the crowded overlapping position of the 
broad short obtuse bluntly-toothed pinnules, which are all connected by the wing of the rachis in 
which they are decurrent. The 
Jour is uniformly a decp bright green. In the more highly 
developed of the fortile fronds the lobes of the pinnules, though still blunt, are more distinct, and they 
have then blunt inconspicuo 
teeth. The sori are situated very near the margin. The pinna are 
twisted more or less from the plane of the frond, as occurs in some 
gree in dentata, from which, with 
the deflexion of the pinne and the frequent confluence of the pinnules, results a pecular aspect, һу 
which this variety is known at first sight. The spores are 
or tubereulate, not 
echinato-tubereulate as in the other varieties, a fact, we believe, first pointed out by Mr, Wollaston, 
The plant was first found by Dr. Dickie on dripping rocks in a cave at Cove, near Aberdeen, and it 
has since been gathered in the same place by several botanists, and by Dr. Balfour, near Dunkeld. In 
cultivation this sometimes produces fronds or pinnas with the apices multifid. 
в. multifida (W.). Tn this, which is not permanent, the apices of the pinna» or of the frond are bifid 
от multifid, or the stip 
