Vascular – Exotic
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
Tall deciduous fern, up to 2 m tall, occasionally with a trunk, fronds of two types, mostly large, up to 3 m long and 75 cm across divided into small flat leaflets up to 7 cm long by 1.8 cm across, with upper fronds sometimes made up of small rounded segments, like a bunch of grapes, turning from green to reddish brown in summer.
Scattered from Northland to Wellington, locally abundant in Waikato.
Fens often under open manuka and grey willow (Salix cinerea), other wet peaty habitats including roadside drains, occasionally on exposed clay banks adjacent to water bodies.
Wetland plant indicator status rating
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Rhizomes forming thick erect trunks to 150 cm tall. Fronds 30-300 × 20-75 cm, ovate, 2-pinnate, glabrous except when very young, dimorphic with the outer ones sterile and inner fertile. Fertile fronds bearing sterile pinnae at base and much reduced fertile pinnae at apex. Sterile secondary pinnae in up to 15 pairs, 2-7 × 0.8-1.8 cm, narrowly oblong, obtuse, ± truncate at base, often with a rounded lobe on one side. Fertile secondary pinnae to 3 × 0.4 cm, densely covered with clusters of sporangia.
No other fern has the combination of deciduous dimorphic fronds.
Late spring to autumn
Late spring to autumn
Perennial. Wind dispersed spores.
Almost cosmopolitan apart from Australasia
Reason for introduction
Ornamental plant or as fibre-bearing plant for orchid cultivation.
Can be controlled manually, mechanically or herbicidally depending on situation.
Tolerates frost, wet, moderate shade, poor and acidic soils.
National Pest Plant Accord species
This plant is listed in the 2020 National Pest Plant Accord. The National Pest Plant Accord (NPPA) is an agreement to prevent the sale and/or distribution of specified pest plants where either formal or casual horticultural trade is the most significant way of spreading the plant in New Zealand. For up to date information and an electronic copy of the 2020 Pest Plant Accord manual (including plant information and images) visit the MPI website.
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Webb et al. (1988).
References and further reading
Webb, C.J.; Sykes, W.R.; Garnock-Jones, P.J. (1988). Flora of New Zealand Volume 4: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch.
Popay et al (2010). An illustrated guide to common weeds of New Zealand, third edition. NZ Plant Protection Society Inc, 416pp.