Art. LVII.—On Hymenophyllum villosum, Colenso.
[Read before the Wellington Philosophical Society, 12th January, 1878.]
This small species has long been a source of perplexity to fern collectors in this colony, by the majority of whom it has been mistaken for Hymeno-phyllum ciliatum, Swartz, a species of wide distribution, but only known in New Zealand from specimens collected in the Nelson district by Mr. Travers. H. villosum was originally discovered by Mr. Colenso in 1842, and described by him in the London Journal of Botany for 1844. Sir William J. Hooker, in “Species Filicum,” referred it to H. polyanthos, β. sanguinolentum, a view which has been adopted by Sir Joseph D. Hooker in his “Flora Novæ-Zelandiæ” and “Handbook of the New Zealand Flora.” It must, however, be regarded as a distinct species, having a wide subalpine and alpine range in New Zealand, although I am not aware of its occurrence elsewhere. I am glad to say that Mr. Baker, who has kindly compared my South Island specimens with those originally sent to Kew by Mr. Colenso, agrees with me as to its specific validity.
Colenso in London Journal of Botany, vol. III., p. 35: Tasmanian Philosophical Journal, vol. II., p. 185.
Rhizome wiry, creeping. Stipes 1–2 inches long, narrowly winged or wingless, villous; frond 2–5 inches high, 1–2 inches broad, opaque, of a dull brownish-green; broadly ovate, or ovate-acuminate, tripinnate, villous; main rachis 1–3 inches long, narrowly winged, flexuose, villous; primary and secondary pinnæ deltoid; tertiary pinnæ twice or thrice divided into narrow linear forked segments. Sori terminal and axillary, free, orbicular, broader than the segments, 2—valved to the base; valves entire.
Hab. On rocks and trees in moist situations.
North Island: Ruatahuna—W. Colenso, 1842; summit of Tarawera (amongst moss), 4,000 feet—T. K.
South Island: Mountains of the Amuri, Nelson, 3,000–4,000 feet—T. K.; mountains above Broken River, Canterbury—J. D. Enys!; Upper Waimakariri and Arthur's Pass, 2,000–3,000 feet—J. D. Enys and T. Kirk; Ashburton—T. H. Potts!; the Routeburn and mountains above Lake Harris, Otago, 4,000 feet—T. K.
I have seen specimens from other parts of the South Island, but am ignorant of the precise localities in which they were collected. In all probability our plant is common throughout the colony at elevations above the highest limit of H. polyanthos, although but rarely occurring below.
The fronds of our plant are more highly divided than those of any other New Zealand species, and present, cspecially in small specimens, a peculiar
crowded appearance, caused by the overlapping of the pinnæ and segments. In small specimens the rachis and stipes are often winged nearly to the base; in the circinate state the fronds are densely clothed with ferruginous hairs; fronds are occasionally found with the lowest pinnæ undeveloped, as in H. multifidum. In its most luxuriant state H. villosum is quadripinnate, and in habit resembles the European Trichomanes radicans, Swartz, when growing in moist situations.
The affinities of our plant are with H. polyanthos, Swartz, and H. demissum, Swartz; from the former it differs in possessing longer and narrower segments and terminal orbicular sori; it may readily be distinguished from the latter by its small size and orbicular involucres, which have entire lips and are broader than the segments. In colour, texture, and the presence of hairs, it approaches H. scabrum, A. Rich., and in the position of the sori and their relative breadth as compared with the segments, it resembles H. javanicum, Spreng. From all the species here named, except H. scabrum, it is distinguished by its villous character.
Mr. Colenso describes the involucres as “ovate,** pedicelled.” I find these characters only in small and imperfectly fruited specimens; the apparent pedicels are simply contracted segments.