This section is from the book "The Florist And Garden Miscellany". Also see: All New Square Foot Gardening: Grow More in Less Space!.
In this genus the involucre is fixed by its wide base to the lower side of the clusters of fructification, a circumstance that readily distinguishes it from Aspidium, Lastraea, and Polystichum; and certainly the difference in position, shape, and substance, warrants the separation from the above genera. Doubtless ere this time C. Dickieana is pretty widely distributed, and will be still more so, as I have ample opportunity of knowing that it is a general favourite with the admirers of British Ferns; in fact, many now appear to concur with me in considering it one of the most distinct forms in the genus; in support of this opinion, the seeds or sporules produce new individuals, identical with the original plant.
With regard to C. alpina, I am much disposed to set it down as a beautiful alpine form of C. fragilis, and approaching closely to C. angustata in some of its stages of growth. It is true, however, that C. alpina appears to be more divided in the fronds, and generally a less plant than the other forms with which I am acquainted. Having disposed of some of the forms of Cystopteris in an article in the Gardeners' and Farmers' Journal of May 13th, 1848, p. 308, I shall here add it to the above remarks.
Whether we consider this to be a species, or only a casual variety, in either case it will doubtless prove, at the present time, a valuable addition to our ferneries, if not to the British Flora. For its discovery, as well as that of other rare British plants, we are indebted to the unwearied exertions of Dr. Dickie of Aberdeen, who detected it, as I am given to understand, amongst rocks by the sea-side in the vicinity of that town, and who very kindly forwarded to me both living plants and dried specimens from its habitat. Its characters appear to run nearly as follows: C. Dickieana, fronds bipinnate, pinnae nearly lanceolate, pinnules almost entire, very obtuse and broad, stipes short.
Notwithstanding this apparent difference between it and the several other forms of Cystopteris, we may easily trace a gradation from C. fragilis to C. Dickieana, depending entirely, I suspect, on circumstances. In the young state of it, the fronds are usually pinnate, and have really much the appearance of Woodsia Ilvensis in that state also, only the latter is invariably clothed with hairs, or scales, which in the present plant are mostly wanting, I believe that I am now cultivating from five to six different forms of Cystopteris, and amongst the rest is a large one, indeed the largest Cystopteris I ever saw, brought from Scotland by my friend Mr. J. B. Mackay, yet, like some of its co-partners, it may readily be referred to C. fragilis. Again, must we not in justice refer C. dentata, C. angustata, and C. alpina, etc, all to one species? I think my plants and specimens from various parts of Britain justify, in a great degree, the above opinion; for really it is difficult to find words sufficient to express what one means, as applied to several of these forms, at least I find it so, and I think, ere long, that others will arrive at the same conclusion.
It is true that many of our monstrosities are readily detected, even at first sight; but when we find it necessary to apply to them for distinguishing characters, they are but too often found wanting, and this may truly be said to apply to Cystopteris. Therefore, if any of the recorded species, apart from C. fragilis, have a claim to rank as such, so also must C. Dickieana.
I am quite aware that the above will be considered a sweeping conclusion to arrive at; but it must be remembered that I take nothing in this way for granted. Nevertheless, I shall not be particularly surprised to find Cystopteris Dickieana ultimately converted into something else.
On the presence or absence of teeth in the pinnules depend our chief divisions in this genus." Robert Sim.