Asplenium Asplenium, (L.) Hoffm.

16. A. septentrionale (L.) Hoffm. View in CoL , Deutschl. FI. (Krypt.) 12 (1795).

Rhizome caespitose, sometimes shortly creeping. Leaves 5-15 cm; petiole 2-3 times as long as lamina, dark reddish-brown only at base, abruptly becoming green; lamina much reduced, thick, dark green, glabrous, dichotomously forked 1-3 times; segments c. 1 mm wide, linear, decurrent along rhachis, minutely forked again at apex. Sori elongate, running whole length of segment. 2« = 144. Siliceous rocks and walls. Throughout Europe except the extreme west and south. Al Au Be Br Bu CoCzDaFeGaGeGrHeHsHuItJuLuNoPoRmRs (N, C, W, K) Sa Si Su Tu.

Hybrids between 16 and 5 a (A. x alternifolium Wulfen , A. x germanicum auct., A. xbreynii auct.) are scattered throughout Europe with the parents. They differ from 16 as follows: petiole equalling to twice as long as lamina, almost entirely dark reddish-brown; lamina pinnate, pinnae c. 2 mm wide, the lowest forked. 2« = 108.