(9) Rue Spleenwort. Asplenium Ruta-murària
Fronds evergreen, small, two to seven inches long, deltoid-ovate, two to three pinnate below, simply pinnate above, rather leathery in texture. Divisions few, stalked, from cuneate to roundish-ovate, toothed or incised at the apex. Veins forking. Rachis and stipe green. Sori few, soon confluent.
This tiny fern grows from small fissures in the limestone cliffs, and is rather rare in this country; but in Great Britain it is very common, growing everywhere on walls and ruins. From Mt. Toby, Mass., and Willoughby Mountain, Vt., to Michigan, Missouri, Kentucky and southward.