Asplenium ruta-muraria, L.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1964, Flora Europaea - Volume 1. Lycopodiaceae to Platanaceae, Cambridge University Press : 16

18. A. ruta-muraria L. , Sp. Pl. 1081 (1753).

Rhizome branched, often creeping; scales very narrow, filiform at apex of rhizome. Leaves 4-15 cm; petiole about as long as lamina, dark only at very base, otherwise green, with occasional glandular hairs; lamina 1-3 cm wide, ovate-lanceolate, glabrous, 2-pinnate; pinnae of 3-5 segments, segments often again similarly divided; ultimate segments 2-3 mm, broadly flabellate to rhombic, apex serrate to incised. Sori linear, sporangia covering whole segment when mature. 2zz= 144. Walls and base-rich rocks. Almost throughout Europe. All except Az Cr Fa Is Sb.

A diploid plant from dolomitic rocks in N. Italy has recently been reported by J. D. Lovis, Brit. Fern Gaz. 9: 143 (1964).