Rhizome filiform, with or without sparse hairs; stipites rather distant to approximate. Stipes filiform, 1-4 cm. long, not winged, with a few hairs at base when young. Rhachis filiform narrowly winged in upper part. Lamina 2-8 cm. long, narrow-oblong, rather dark green, pinnate to pinnatifid; segs developed on abaxial side of pinnae, linear, coarsely toothed. Sori on short lateral segs near base of abaxial side of pinnae, free or nearly so. Indusium c. 1·5 mm. long, broadly oblong, deeply 2-valved; valves with entire to minutely crenulate margins. Receptacle included.

n = 11

This species, when growing in exposed places (Fig. 4 d, e), may resemble H. revolutum in habit and in possessing a solitary sorus, but the entire margin to the valves and the rachis winged throughout are constant differences. Typical H. peltatum (Fig. 4 a-c) is approached in habit by a form of H. revolutum (Fig. 3 a, b) which has the margins of its valves crenulate or only slightly denticulate. The branching of the pinnae is less bilateral than in many forms of H. revolutum, but the wing on the rachis does not extend past halfway. It is this form that grows with H. peltatum on the summit of Mt Te Aroha, South Auckland, but no intermediates have been seen there. No material that could be construed as intermediate between H. revolutum and H. peltatum has been seen. H. cupressiforme resembles H. peltatum more closely. Typical specimens of each should never be confused, but the elongate forms of H. cupressiforme with nearly entire indusial margins (H antarcticum), could be mistaken for the coarser forms of H. peltatum with only solitary sori. In these cases the most reliable distinctions are the shape of the indusia and the extent of the wing on the rachis (Figs. 2 c, 4 b, both basal pinnae). In H. peltatum the wing on the rachis is very narrow at the base and if it extends to the top of the stipe is only one cell thick and hardly visible. In H. cupressiforme the wing is distinctly wider at the base of the rachis and usually clearly visible at least halfway down the stipe.