This section is from the book "The Florist And Garden Miscellany". Also see: All New Square Foot Gardening: Grow More in Less Space!.
This genus is readily distinguished from any of the preceding genera by the absence of the involucre or iudusium.
It is scarcely necessary to offer any remarks on the cultivation of this common British Fern, as we find it growing in almost all soils and situations. It certainly, however, luxuriates most on the decayed stumps of trees in shady woods and hedge-banks. The fronds are pinnatifid.
Like many other monstrosities, the P. cambricum far surpasses the original form in elegance, as the lobes or segments are all deeply and beautifully notched on their margins, characters which it appears to retain under every sort of cultivation. As an instance of the esteem in which this elegant British Fern is held, I may mention that I send out more of it than of any other kind that I possess, either native or exotic; this is easily accounted for, as, in all probability, the original station or stations afforded only one solitary plant each, and for many years it may have had to depend upon cultivation for its existence.
In this the segments are divided at their extremities; and this is the only difference that exists between it and the normal form. There are also a P. vulgare, var. serra-tum, and some other very slight variations, which I consider to be scarcely worthy of notice.
A very accommodating Fern under cultivation; if planted in a dry part of the fernery in loam and peat, it will increase rapidly, as it has a creeping root. It is usually found wild in the north of England and Scotland, growing on old stone walls and masses of broken rock, where it is exposed to all kinds of weather; it therefore may be considered extremely hardy, and well calculated for all the purposes of out-door planting.
This is not quite so plentiful as the last, and generally affecting to grow in rather moist situations, among rocks and loose stones, in sub-alpine countries, and more especially where there is a little shade. Notwithstanding the difference in their natural habitats, it appears to submit to cultivation equally freely with P. dryopteris. They both thrive well with me in dry and exposed situations. Root also creeping.
Some years ago, when we were comparatively strangers to each other, I found this Fern rather shy and impatient under cultivation; in fact, I had been in the habit of losing my entire stock for several winters in succession, until I found out that the roots were disposed to resist both my fingers and the knife, which, I confess, were at times unsparingly applied to them; I would therefore recommend its being planted out in unbroken masses, if from its habitats, and if out of pots, with the balls of earth entire. It requires a more sheltered situation than either of the preceding, as it is generally furnished with longer stems.
I have now arrived at that part of my remarks on this genus, where it may be expected that I should say something relative to the distinctive characters of the last species, more especially as it has often been suggested to me that they were no more than different forms of the same plant. To this I can only reply, that I have cultivated them for many years, and always found them to retain their respective characters. Notwithstanding that P. calcareum is usually found upon chalk and limestone formations, it appears the same after many years' cultivation as when taken from its habitats, indeed if it had been disposed to run into either of the two, I think I must have observed the transition.