Flora of New Zealand Series

Aspidium cystostegia Hook. Sp. Fil. 2, 30, t. 127. 

J. B. Armstrong in T.N.Z.I. 13, 1881, 364 listed "P. cystostigium (Hk)" without further citation.

Rhizome stout, branched, erect, densely clad in pale brown ovate-acuminate paleae up to 15 × 5 mm.; stipites few to many, densely clustered. Stipes rather stout, 5-15 cm. long, densely clad in similar but often narrower paleae, mingled with slender hairs. Rhachis rather stout, shallowly grooved, sts winged, paleate and hairy, with numerous approximate to rather distant pinnae. Lamina lanceolate to oblong-lanceolate, soft, membr., pale green; ± hairy, especially when immature; 8-15-(30) × 3-5-(10) cm. Larger pinnae 1-4 cm. × 10-15 mm., about ovate, again pinnate or pinnatifid. Pinnules or segs up to 1 cm. long, ovate to lanceolate, crenately toothed. Sori 2-4 per pinnule, nearer veins than margin, c. 1-2 mm. diam.; indusium very convex, thin, pale.

DIST.: N., S., St., A., C. Higher montane to subalpine shrubland and rocky places from lat. 39º southwards. Endemic.

HYBRIDISM

The spp. as at present understood are aggregates, but part of the polymorphy observed appears to be due to hybridism. The following hybrid groups have been listed, tentatively, by Cockayne and Allan: P. cystostegia × vestitum, P. richardii × silvaticum, P. richardii × vestitum, P. silvaticum × vestitum. All but the first are based on observations by Carse.

Originally described from specimens collected by Dieffenbach in 1840, probably on Mount Egmont, but ascribed to Mount Tongariro, which Dieffenbach did not visit.

P. mohrioides (Bory) Presl was recorded for Auckland Islands by Kirk in T.N.Z.I. 14, 1882, 386 : "Fronds tufted, 3-5 inches in length, scarcely more than an inch in width; stipes very short, covered with soft brown scales mixed with hairs; frond oblong or oblong-lanceolate, pinnate, pinnae in about twelve pairs, close set and imbricating, the lower shortly stalked, ovate, pinnate or pinnatifid, segments close set, crenate, obtuse; sori crowded, restricted to the upper part of the frond, indusium smooth, attached by the centre . . . In the chaffy habit and membranous texture our specimens approach A. cystostegia, but the lax pinnae and acute segments of the latter afford easy marks of distinction." The specimens appear to be lost, but small plants of P. cystostegia with obtuse crenate segments have been collected on both Auckland and Campbell Islands. A single plant, since dead, was observed on a dry Leptospermum ridge near the sea on Kapiti Islands by Mr A. Wilkinson. Fronds sent to the Director of the Royal Botanic Gardens were identified as belonging to a form of P. mohrioides, an identification confirmed by the late M. L. Fernald. Stipes up to 16 cm. long, stout, asperous. Paleae dark brown, linear-subulate, up to 1 cm. long. Lamina coriac., up to 28 cm. long, linear. Pinnae numerous; lower often up to 3 cm. long, pinnate or pinnatifid; mid flabellate, c. 7 × 10 mm., very shortly stalked, crenately toothed or dissected; upper smaller, decreasing to acuminate apex.