Flora of New Zealand Series

Rhizome short, stout, branching, often forming rounded mass; clad in translucent ovate-attenuate paleae c. 15 × 3 mm.; stipites tufted, with dense tuft of paleae at base. Stipes stout to slender, firm, (1)-10-30 cm. × 5-10 mm., us. densely clad in shorter paleae when young, dark brown towards base, green in upper part, grooved, ± compressed. Rhachis narrowly winged, stout to slender, pale green, bearing numerous alt. pinnae. Lamina submembr., rather pale to dark green, ovate-oblong-lanceolate, acuminate, bipinnate to pinnatisect, (5)-30-80-(120) × (2)-10-20-(30) cm. Pinnae ovate-lanceolate, shortly stalked, acuminate, spreading at wide angle, (2)-10-15-(25) × (1)-3-5-(7) cm.; costa winged. Secondary pinnae decreasing in size to apex of primary pinna; lower ovate-oblong to lanceolate, obtuse, up to 4 cm. × 15 mm.; upper pinnatisect, segs up to 15 mm. long, about oblong, obtuse; margins crenate to crenate-serrate to subentire. Sori numerous, broad-oblong, submarginal, 2-5 mm. long; indusium firm, obscured by mature sori. Bulbils on veinlets of upper surface, with fronds up to 8 cm. long before falling.

There is a considerable range in stature and plants only 10 cm. tall may bear sori.

DIST.: N., S., St., Ch., A. (Rata forest, W. Dawbin), Ant. Common in lowland to lower montane forests throughout. Endemic.

 Var. laxum Hook. f. Fl. N.Z. 2, 1855, 34, "frondibus saepius pendulis minoribus." A. laxum R. Br. Prodr. 1810, 151, "frondibus bipinnatis lanceolatis glabris flaccidis, pinnulis incisis pinnatifidisve inferiori basi antice productiori, laciniis lineari-lanceolatis unifloris, involucris semi marginalibus . . . Nimis affine Asplenio bulbifero Forst., sed nunquam proliferum vidi." Cheeseman (Man. N.Z. Fl. 1925, 50) has: "Fronds smaller and more slender, with narrower and more remote pinnae. Pinnules more deeply divided; segments narrow-linear. Sori often marginal."

Plants ± answering the descriptions occur in the main islands. Lamina 20-40 × 10-20 cm. Primary pinnae distant, up to 10 × 4 cm., again pinnate, except at pinnatisect apical portion. Secondary pinnae up to 25 × 10 mm., about ovate-oblong, pinnatifid to pinnatisect; segs oblong, obtuse to subacute, entire or toothed. Sori c. 2 mm. long, submarginal. Bulbils are rather rare on these forms.

A. gracillimum Col. in T.N.Z.I. 22, 1890, 453, was described from plants collected on "Dry sides of hills, shady woods south of Dannevirke, County of Waipawa (where it is plentiful); 1888, 1889: W.C." The type in W (Dannevirke, W.C.) is one complete plant. Stipes c. 13 cm. long, slender, with tuft of paleae at base c. 1 cm. long, clad throughout in slender linear-attenuate paleae. Lamina 24 × 13 cm., ovate-acuminate. Primary pinnae about 26, 8 × 3 cm., secondary pinnae distinctly stalked, up to 10 × 10 mm., ovate-oblong, again pinnatisect to pinnatifid; segs oblong, us. toothed; indusium delicate. Colenso compares it to A. hookerianum, and further study is desirable.

A. triste Raoul in Ann. Sci. nat. Sér. 3, 2, 1844, 115, from "Akaroa in nemoribus umbrosis" is described in Raoul's Choix p. 10, as "A. frondibus ovato-oblongis, bipinnatis (superne simpliciter pinnatis); pinnis ovato-lanceolatis, dentatis, inferioribus oppositis, pinnatis; pinnulis ovatis, dentatis, brevi stipitatis (Filix 3-4 decimetr.; stipes caniculatus, squamis gracilibus, lividis, longissime acuminatis, inspersus." It is not referred to by Martin (T.N.Z.I. 52, 1920, 315-322) but deserves further investigation.

 Var. tripinnatum Hook. f. Fl. N.Z. 2, 1855, 34. A. tremulum Homb. et Jacq. Voy. Pôle Sud 1853, t. 3 bis. Hooker's description is: "fronde erecta ampla, pinnis secundariis pinnatis, pinnulis oblongo-lanceolatis stipitatis obtuse crenato-lobatis." Cheeseman (loc. cit. p. 51) has: "Fronds ample, tripinnate, with narrower pinnules and segments resembling some forms of A. flaccidum, but more compound and texture thinner." Forms ± answering the descriptions are not uncommon (see illustration Dobbie New Zealand Ferns 1951, p. 350) but intermediate forms also occur.

J. B. Armstrong (T.N.Z.I. 14, 1882, 361) described his A. canterburiense from specimens collected on Mount Arrowsmith and Mount Torlesse by J. F. Armstrong and near the Waimakariri Gorge by himself. Its differential characters are given as: "Fronds lanceolate, sub-coriaceous, bipinnate, pubescent. Pinnae lanceolate, or deltoid-cuneate, sori covering the whole under surface." The indusium is given as "fixed in the centre of the segment." There is a specimen in the Armstrong herbarium (now in CM) labelled: "Mount Arrowsmith-4000 feet alt. Mr. J. F. Armstrong Mch 1869." It differs from A. richardii in that the secondary pinnae, except lowest, are neither pinnatisect nor pinnate, but mostly ± entire. They are not pubescent. The sori cover most of the under surface. The lamina is c. 14 × 6·5 cm. Armstrong refers his sp. to the "series represented by A. bulbiferum, A. colensoi, A. richardi, and A. hookerianum." It appears nearest to A. bulbiferum.

In the Armstrong herbarium are specimens labelled A. bulbiferum var. minimum, "Summer 1864, J.B.A., on dry rocks". These are dwarf specimens, fertile when only 2-3 cm. tall. The status deserves study. A specimen labelled "A. bulbiferum var. trifidum, Port Hills (Christchurch) J.B.A." shows a frond with rhachis tripartite from base, with linear segs. Similar abnormal forms have been collected, but the cause has not been studied.