Alternate Leaved SpleenwortALTERNATE-LEAVED SPLEENWORT
The Alternate Leaved Spleenwort is very like the Smooth Rock Spleenwort, and is perhaps only a variety, but the segments are much narrower. It grows in little tufts. The whole frond is narrow usually-simply pinnate-with the lower segments three-lobed, or very rarely bearing three distinct segments. The pinnae have two or three distinct lines of sori crowded on their under surface, which ultimately meet in the centre. The indusium is entire at the edge, not jagged, as in the Wall Rue.
This is, perhaps, the rarest of our British ferns. There is little to distinguish it from A. Ruta muraria. It has very seldom been found in England, Wales, or Ireland, and rarely in Scotland. Mr. Newman mentions three localities there where it has been gathered; viz. - near Dunfermline, Dunkeld, and on rocks on the Tweed, two miles from Kelso. In other parts of Europe it is occasionally seen, but grows very sparingly.
The scarcity of this fern prevents our saying much as to its artificial growth in the open air.
It is much prized in Germany and the south of France, and is frequently brought here from thence as a foreign plant. We have seen it growing luxuriantly in a glass case, in the smoky atmosphere of London; but it is seldom that it succeeds so well in artificial circumstances. In attempting its cultivation, however, care must be taken that moisture should not accumulate on the fronds, or stagnate about the roots; it must be kept as dry as possible without causing positive drought.