262 THE BRITISH FERNS. 
turfy peat and loam, with sand, in equal parts. It does not require 
pots of large size, and the drainage should be ample. Few Ferns 
are more easily cultivated than this, for although growing more 
luxuriantly when planted in prepared soil and in a situation corres- 
ponding to its natural habitat, yet it does not refuse to grow in any 
ordinarily good earth, provided it is porous and well drained. Mr. 
Johnson observes that it may be grown in the open border, and 
if not too fully exposed to the sun, forms beautiful and elegant tufts 
that contrast well with the smaller species of herbaceous plants, 
requiring only the occasional removal of its rapidly maturing fronds 
to maintain throughout the summer thelively green appearance of the 
masses. The delicate feathery character of the foliage, he con- 
tinues, renders it a favourite species for pot culture, and in a cool 
greenhouse it becomes highly ornamental; but it is not well adapted 
for planting in closed cases, though often recommended, the 
slender rachis being too rapidly extended in the damp confined 
atmosphere to support the lengthened frond. All the British 
forms of this Cystopteris, are seen under cultivation to the greatest 
advantage when planted on shaded rock-work. Like other rock 
and wall plants, they require good drainage, a condition readily 
effected by the admixture of about one-fourth of small fragments of 
old mortar with the soil or compost employed. The value of this 
addition is indieated by the natural preference the species seems to 
evince for limestone districts. The plants increase readily by divi- 
sion, or from the spores. 
The fronds of this Fern, and of some others of similar texture, 
are frequently damaged by the ravages of a yellow fungus (Uredo 
filicum), which spreads rapidly and soon spoils those plants which 
are seriously attacked. It occurs most commonly on plants grown 
in houses, and might hence be supposed to be owing to the confined 
dampness generally maintained in structures where Ferns are grown; 
but this is not the case, for we have found native specimens from 
Ben Lawers and from Ireland similarly affected. 
There are no very definite limits to the variations of this species, 
cven when exotic forms are excluded, except in the case of the 
variety Dickieana which is well-marked and permanent; still there 

