Onoclea sensibilis L.

Onoclea sensibilis is recognised by its long-creeping, scaly rhizomes and strongly dimorphic fronds. The sterile fronds are deeply pinnatifid distally, and either deeply pinnatifid or 1-pinnate-pinnatifid proximally, broadly ovate, herbaceous to papery, more or less glabrous and with reticulate veins. The primary pinnae are narrowly elliptic, with acute to obtuse apices and entire to deeply lobed margins. The fertile fronds are much narrower than the sterile fronds, 2‑pinnate, linear, coriaceous and with free veins. The primary pinnae are linear and the blade reduced to very short, rounded, bead-like secondary pinnae. The sori are round and enclosed by the strongly inrolled margins of the secondary pinnae. Indusia are present but not easily seen in mature fronds. The fertile fronds persist for 2–3 years but the sterile fronds are deciduous, at least in the northern hemisphere, surviving as swollen storage organs over winter.

Recorded as growing in crevices between concrete slabs near a stream.

Heenan et al. (2004, p. 803). Voucher CHR 509661, 1996.

A specimen of Onoclea sensibilis was collected from “Mr Baltrop’s garden, Nelson” by Marguerite Crookes in January 1958 (AK 50966). Conceivably this was the source of the material that became naturalised in Nelson.