Hymenophyllum Sm.

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 : 13

1. Hymenophyllum Sm. 1

Very small, with the habit of bryophytes, and often growing with them. Rhizomes filiform, less than 1 mm in diameter, smooth. Leaves more or less procumbent, persistent after withering, forming a dense mat of foliage, deeply pinnatisect, the segments asymmetrical, subentire on their proximal side, deeply lobed on their distal side with 2-15 oblong, obtuse, dentate lobes. Sori solitary, more or less globose, situated near the base of the distal segments of the frond; indusium of 2 ovate or suborbicular valves, united only at the base.

Literature: E. B. Copeland, Philipp . Jour.Sci. (Bot.) 64: 1 (1937).

Valves of indusium dentate; leaves bluish-green 1. tunbrigense

Valves of indusium entire; leaves somewhat olive-green 2. wilsonii