Species

Osmunda regalis

Common Name(s)

royal fern

Authority

Osmunda regalis L.

Family

Osmundaceae

Brief Description

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.

Flora Category

Vascular - Exotic

NVS Species Code

OSMREG

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.

Structural Class

Ferns

Distribution

Scattered from Northland to Wellington, locally abundant in Waikato.

Habitat

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.

Features

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.

Similar Taxa

No other fern has the combination of deciduous dimorphic fronds.

Flowering

Late spring to autumn

Flower Colours

No Flowers

Fruiting

Late spring to autumn

Year Naturalised

1890

Origin

Almost cosmopolitan apart from Australasia

Reason for Introduction

Ornamental plant or as fibre-bearing plant for orchid cultivation.

Control Techniques

Can be controlled manually, mechanically or herbicidally depending on situation.

Life Cycle and Dispersal

Perennial. Wind dispersed spores.

Tolerances

Tolerates frost, wet, moderate shade, poor and acidic soils.

Attribution

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.

This page last updated on 21 Aug 2013