North Island: Hilly forests from the Great Barrier Island (C. P. Winkelmann!) and Cape Colville southwards, not common to the north of the East Cape. South Island, Stewart Island, Chatham Islands: Not uncommon throughout. Sea-level to 3000 ft.
Confined to New Zealand. Allied to H. multifidum, but a larger and less rigid plant, of a paler-green colour, and with smaller indusia immersed in the tips of the segments, not axillary.
2. TRICHOMANES, Smith.
Ferns, usually of small size. Rhizome slender or rather stout, often much branched, glabrous or tomentose. Fronds compound or rarely simple and entire, of the same delicately membranous texture as Hymenophyllum, often pellucid, usually of a single layer of cells, rarely of 3–6 layers. Ultimate segments linear or narrow-oblong, entire or rarely toothed at the margin, with a stout central costa. Sori marginal, terminal or lateral, more or less immersed in the frond or quite free, always terminating a vein. Indusium tubular or trumpet-shaped, truncate at the mouth or with a narrow spreading lip or border, usually of the same texture as the frond. Receptacle elongated, filiform or columnar, usually exserted beyond the indusium. Sporangia sessile, depressed, surrounded by a broad complete horizontal ring, bursting transversely.
A genus of about 90 species, of almost precisely the same geographical range as Hymenophyllum, and agreeing with it in habit and in the delicate texture of the frond, but differing in the shape of the indusium, which is cylindrical or urceolate, and either truncate at the mouth or very shallowly 2-lipped. Of the 7 species found in New Zealand, 4 appear to be endemic, 2 occur in the Polynesian islands, one of them extending as far north as Java, the remaining one is found in Australia and Tasmania.
| * Fronds simple and entire. | |
| Fronds 2–4 in. diam., broadly reniform with a deep sinus | 1. T. reniforme. |
| ** Fronds small, ½–4 in. long, usually pendulous, delicately membranous, pinnately or 2-pinnately divided; divisions comparatively few. | |
| Fronds ¾–1½ in., digitately or flabellately divided, margins ciliated with branched rufous hairs. Indusium obconical, immersed | 2. T. Lyallii. |
| Fronds 1–3 in., dull dark-green, irregularly 2-pinnatifid, segments with a single unbranched costa | 3. T. humile. |
| Fronds 1–4 in., pale-green, irregularly 2-pinnatifid, costa of the segments giving off numerous dichotomous veinlets | 4. T. venosum. |
| Fronds 1–4 in., dark-green, 2–3-pinnately divided; rhachis not winged. Segments very narrow-linear, acute; costa not branched | 5. T. Colensoi. |
| *** Fronds larger, 4–9 in. long, rigidly erect, subcoriaceous, 3–4-pinnatifid; divisions numerous. | |
| Fronds lanceolate, pale yellow-green; ultimate segments narrow-linear, obtuse | 6. T. strictum. |
| Fronds ovate-deltoid, dark-green; ultimate segments broad, oblong, incised at the tips | 7. T. elongatum. |
