Questions? AskAuckland

NZ Plants

Pteridium esculentum - rārahu, bracken fern

Family: Dennstaedtiaceae

Pteridium esculentum is a terrestrial fern with a robust, long-creeping, underground stem (rhizome). The large, broadly elliptic fronds have a woody stem (stipe) and midrib (rachis) with stiff, leathery leaflets curled downwards at the margins
Found throughout New Zealand in open places, aggressively invading cleared land..


Vegetative characteristics

Fertile frond and sporangia

Plant form: creeping stem (rhizome) with fronds up to 2 m in length

Frond appearance: same as sterile

Frond stalk, midrib: woody, grooved with sparse hairs

Sporangium location: lower frond surface

Frond shape: ovate to elliptic

Sporangium position: leaflet margin

Frond blade: 3-4-pinnate (divided up to 4x into leaflets or pinnae)

Sporangia distribution: in groups (sori)

Frond surface: sparse hairs on under surface

Sorus shape: continuous along leaflet margin

Leaflets: linear attached along their base (adnate)   

Sorus covering: a reflexed leaflet margin and an inner membranous covering.