Art. LXXIV.–Description of a new Species of Hymenophyllum.
[Read before the Wellington Philosophical Society, 11th January, 1870. Hymenophyllum rufescens, n. s.
Rhizome creeping slender; stipes, costa and veins when young sparingly clothed with deciduous curved hairs; stipes, very slender, 1–2 inches long, longer than the frond; frond 1–1 ½ inches long, deltoid, sometimes cuneate at the base, pinnate, rachis winged above the second
pair of pinnæ; pinnæ twice pinnatifid, unequally rhomboid, the lowest pair divided nearly to the mid-rib; the basal pinnules spreading; capsules, terminal, small, half immersed, divided nearly to the base, hairy when young, margins entire or erose.
Hab: North Island–near the source of the Orua, Ruahine Mountains; 2,000 to 3,000 feet, H. Field, junr.! South Island–Okarito, A. Hamilton.
The affinities of this fern are with H. æruginosum, Carm. (H. subtilissimum, Kunze), and with H. flabellatum, Swartz. From the former it differs in the deltoid frond, in the form of the pinnæ, in the long and slender stipes, as well as in the delicate texture and partial hairiness. It resembles the latter in the shape of the pinnules, but differs in the stipes being longer than the frond, which is never ovate or linear, and the pinnules are never crowded. In habit our plant differs widely from both; in texture and colour it resembles Trichomanes lyallii.
The stipes, rachis, costa, veins and involucres are usually hairy, at least when young; but hairs are rarely produced from the surface of the frond; in H. æruginosum they are developed from both surfaces, and from the margins of the frond as well as from the veins; they are usually straight, and never deciduous as in our plant, my oldest specimens of which have very few hairs. The valves of the capsule are minutely erose in my young specimens from the Ruahine mountains, but this character is not developed in the mature specimens from Okarito.
This species was originally discovered by Mr. Field in the Ruahine mountains, and I was indebted to Mr. H. C. Field of Wanganui for a single young frond as far back as the early part of 1877, but it was not until the receipt of a supply of specimens from Mr. Hamilton, that I was able to satisfy myself of its specific validity.
Description of Plate XIX., Fig. A.
Hymenophyllum rufescens, nat. size.
1, 1. Pinna with capsule from old frond, enlarged.
2, 2. Pinna and capsule from young frond, enlarged.