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NZ Plants

Cyathea medullaris - mamaku, black tree fern

Family: Cyatheaceae

Cyathea medullaris is a tall tree fern characterised by black frond stalks (stipes) and fronds arching upwards from the crown.  Shedding of old fronds occurs when stipes break at their point of attachment to the trunk leaving a surface with closely-spaced hexagonal leaf-base scars.
An endemic species found on the North Island south to Dunedin on the South Island.

Vegetative characteristics

Fertile frond and sporangia

Plant form: trunks up to 20 m bearing fronds up to 5 m in length

Frond appearance: similar to sterile frond

Frond stalk, midrib: scales with marginal spines

Sporangium location: on lower frond surface

Frond shape: elliptic

Sporangium position: away from leaflet margin

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

Sporangia distribution: in groups (sori)

Frond surface: scales on underside

Sorus shape: circular

Leaflets: oblong, round- toothed margins, pointed at the tip; attached along leaflet base (adnate)

Sorus covering: spherical covering (indusium)