Cyathea medullaris

From Wikipedia, the free encyclopedia

iBlack Tree Fern

Scientific classification

Kingdom:	Plantae
Division:	Pteridophyta
Order:	Cyatheales
Family:	Cyatheaceae
Genus:	Cyathea
Subgenus:	Sphaeropteris
Section:	Sphaeropteris
Species:	C. medullaris

Binomial name

Cyathea medullaris
(G. Forster) Swartz, 1801

Synonyms

Polypodium medullare G. Forster, 1786
Sphaeropteris medullaris (G. Forster) Bernhardi, 1801
Cyathea affinis W. J. Hooker & Baker, 1874 (non Cyathea affinis (J. R. Forster) Swartz, 1801, non Cyathea affinis M. Martens & Galeotti, 1842 (cannot be attributed to any species), non Cyathea affinis Brackenridge, 1854; quae Cyathea propinqua)
Alsophila extensa Desvald, 1827 (non Alsophila extensa Blume, 1828; quae Cyathea raciborskii)
Alsophila lunulata (G. Forster, 1786) R. Brown, 1827 (non Alsophila lunulata Blume, 1828; quae Cyathea junghuhniana)

Cyathea medullaris, popularly known as the Black Tree Fern, is a species of tree fern endemic to New Zealand. It is called Mamaku, Katātā, Kōrau, or Pītauin in Māori.

This fern is found to grow to heights of 20 m, making it the largest tree fern. It is an evergreen species - the New Zealand bush is evergreen due to the mild climate. Groups of lightly interspersed black tree ferns are common sights and very prominent on the rather steep but overgrown slopes of the North Island volcanic landscape (see picture below).

It may have been named because the base (the stipe) of each mature frond is black with a rather bluish tinge if seen from the underside. Also, the fiddleheads are covered in a dark brown furry layer of plant material.

To the casual observer, black tree ferns with their typical habitus might look more akin to palm trees than to woody trees, but they are not closely related to either. Its fronds have rather little overlap and do not shade each other very much.

It has no secondary growth (see meristem) and no wood. Nevertheless, tree fern stalks, including black tree fern, have been used as building material and they are still used for makeshift trackwork.