T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Whau (Corkwood) Entelea arborescens

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Malvales
Family: Malvaceae
Subfamily: Grewioideae
Genus: Entelea
Species: E. arborescens
Binomial name: Entelea arborescens
Common names: Whau, Corkwood, New Zealand mulberry, Evergreen lime

Entelea arborescens or whau is a species of malvaceous tree endemic to New Zealand. E. arborescens is the only species in the genus Entelea. It is a shrub or small tree to 6 m with large lime-like leaves giving a tropical appearance, whau grows in low forest along the coast of the North Island and the northern tip of the South Island. The dry fruit capsules are very distinctly brown and covered with spines.
As is the case with most malvaceous plants, E. arborescens has alternate, stipulate foliage. The bright green obliquely cordate leaves are large (10 to 20 cm long), and have from 5 to 7 nerves and long petioles.

The white flowers are borne profusely between early spring and mid-summer. They have 4 or 5 sepals and petals. They are 2 cm in diameter, scented, white, with a central bunch of densely-packed yellow stamens. The brown seed capsules, which are 1½ cm long, bear 2½ cm long rigid bristles.

The species is extremely light-demanding and is unable to live under an unbroken canopy. It cannot tolerate even moderate cold, strong wind, or a very dry or ill-drained soil. Its occurrence is sporadic even in undisturbed coastal forest. In lowland rain-forest whau is rare, found only beside streams in valleys near the coast where open ground and sufficient warmth and light are found. In its natural habitat the tree depends mainly for success upon its prodigious seed production, the remarkably long life of the seed, and, after germination, rapid growth. In forest, whau is essentially a transient, opportunist species. The characteristics which cause it to be effective in such arole include: its ability to quickly occupy ground where light has been temporarily let into the forest; its tremendous rate of growth; its ability to rapidly produce fruit; its enormous seed production, especially as it is about to die; and the fact that its seeds are capable of germinating as soon as the capsules open. Whau seeds can be stimulated into growth by fire after lying on the surface of the ground for many years. Having germinated, whau establishes itself with striking rapidity, and where conditions are favourable, whau is often the first new plant to appear, followedby Urtica ferox, Macropiper excelsum, Coprosma macrocarpa and Coprosma australis. Forest-dominating trees are slower to come in; Corynocarpus most quickly, followed by Beilschmiedia tawa.

Whau has very light wood, rivalling balsa (Ochroma pyramidale) for lightness, and less dense than cork. The wood was used by Maori for the floats of fishing nets and the like. The pale brown wood forms several bands of unlignified pith-like parenchyma per year. This is a characteristic shared with related plants including Sparrmannia, and means that there are no distinct growth rings in the wood.

Whau flowers developing early October. See tiny Black spined weevil on buds. (http://www.terrain.net.nz/friends-of-te-henui-group/local-insects/weevil-black-spined-scolopterus-penicillatus.html