9. CYSTOPTERIS, Bernh.
Small membranous and flaccid ferns. Rhizome very short, creeping. Fronds tufted, 2–3-pinnatifid. Veins pinnate and forked; veinlets free, not anastomosing, terminating a little within the margin. Sori small, globose, dorsal, placed at a distance from the margin on the back of a vein. Indusium ovate-deltoid, membranous, jagged, free at the sides, inserted by a broad base under the sorus, and at first bent over it like a hood; ultimately reflexed. Sporangia numerous, stalked, girt by an incomplete vertical ring, bursting transversely.
A small genus of 5 species, found in cool damp mountainous situations in the temperate regions of both hemispheres. The single New Zealand species has the range of the genus.
1. C. fragilis, Bernh. in Schrad. Neu. Journ. Bot. ii. 27, t. 2, f. 9.—Rhizome short, suberect, often branched near the top, clothed with red-brown lanceolate scales. Stipes 1–4 in. long, slender, fragile, stramineous, slightly scaly at the base. Fronds 3–9 in. long, 1–2 in. broad, oblong-lanceolate or ovate-lanceolate, thin and membranous, pale-green, pinnate or 2-pinnate; rhachis smooth, naked, slightly winged above. Primary pinnæ rarely more than 1 in. long and usually much less, remote, spreading, lanceolate to ovate, toothed or pinnatifid or again pinnate; pinnules oblong, usually deeply toothed or incised. Sori 3–12 to a pinnule, medial on the veins. Indusium very delicate, at first covering the sorus, but soon reflexed and often disappearing in age.—Hook. Sp. Fil. i. 197; Hook. f. Fl. Tasm. ii. 136, t. 166; Handb. N.Z. Fl. 358; Hook. and Bak. Syn. Fil. 103; Benth. Fl. Austral. vii. 752; Thoms. N.Z. Ferns, 50; Field, N.Z. Ferns, 76, t. 18, f. 5, 5a. C. tasmanica. Hook. Sp. Fil. i. 199; Ic. Plant, t. 959. C. novæ-zealandiæ, Armstr. in Trans. N.Z. Inst. xiii. (1881) 360. C. laciniatus. Col. in Trans. N.Z. Inst. xxxi. (1899) 265.
North Island: Mount Egmont, Mrs. Jones, T.F.C.; Tararua Ranges, Buchanan; Wairarapa Valley, H. C. Field. South Island: Not uncommon in mountain districts throughout. Usually from 1000 to 4000 ft., but descends almost to sea-level in several localities in the South Island.
Almost universally distributed in the north and south temperate zones and on the higher mountains of the tropics, and everywhere extremely variable. The usual form in New Zealand has a rather narrow frond, with short and broad sparingly divided pinnæ, and the sori are rather small. But some states are almost indistinguishable from the northern var. dentata. I have seen no specimens of Mr. Colenso's C. laciniatus.
10. LINDSAYA, Dryander.
Usually small subcoriaceous bright-green ferns. Rhizome creeping or short and tufted. Fronds pinnate or 2–3-pinnatifid; pinnæ often 1-sided. Veins free, or anastomosing in a few species not found in New Zealand. Sori forming a continuous or more
