Passiflora tetrandra < Species index > Pennantia corymbosa
This article was first published in the Tararua Tramper Volume 96, # 11, December 2024
December in the hills with Michele Dickson and Chris Horne
Pellaea rotundifolia, Tarawera, pellaea, Round-leaved fern, Button fern, NZ cliff brake
Photo: Jeremy Rolfe
Photo: Jeremy Rolfe
For general comments about ferns, see Asplenium oblongifolium, and a description of the life cycle of ferns in Asplenium bulbiferum.
Origin of the botanical name
Pellaea comes from a Greek word meaning ‘dark-coloured’; rotundifolia comes from a Latin word meaning ‘round-leaved’. Pellaea is in the Pteridaceae family.
Distribution and habitat
Round-leaved fern / tarawera is native to New Zealand where it occurs on Manawatāwhi / Three Kings Islands, Te Ika a Māui / North Island, Te Waipounamu / South Island and Rekohu / Chatham Island. It also occurs on Norfolk Island and in Australia - thus it is native to Aotearoa but it is not endemic. It is common on the ground in drier native forests, in light scrub and sometimes in the open throughout its range.
Growth habit and reproduction
Round-leaved fern / tarawera grows in native forests, mainly at lower levels. The creeping rhizome / underground stem is rather stout and when young is clad with brown scales ca. 3 mm long. The stipes / stalks, 5-15 cm long, are stout, upright or procumbent / lying flat on the ground. They are dark reddish brown with projecting points. The rachis / stem is similar to the stipes – it bears up to thirty or more pairs of sub-opposite or alternate pinnae / parts arranged on either side of it. The dark green pinnae are rounded or oblong, abruptly narrowed to a short apical point and have margins minutely toothed. The narrow frond blade / overall rachis and pinnae is 11-87 cm long x 1.8 - 4 cm wide. The sori which contain spores coalesce in broad bands near the margins of the pinnae except at either end.
Use
We have not been able to find any uses for tarawera except as a house plant – some plant nurseries stock it.
Where to find round-leaved fern?
Look for it in the Tararua, Remutaka and Aorangi ranges, in reserves in the Wellington area and wherever you tramp in native bush.