Entelea arborescens (Whau)

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 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 the low forest along the coast and the lowland forests of the North Island, the northern tip of the South Island and the Three King islands. 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. These large thin leaves are easily damaged by frost and wind.
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 tree only last for 20 years.
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 the undisturbed coastal forest. In lowland rain-forest, E. arborescens 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 the forest, E. arborescens is essentially a transient, opportunist species. The characteristics which cause it to be effective in such a role 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. E. arborescens seeds can be stimulated into growth by fire after lying on the surface of the ground for many years. Having germinated, E. arborescens establishes itself with striking rapidity, and where conditions are favourable, E. arborescens is often the first new plant to appear, followed by Urtica ferox, Macropiper excelsum, Coprosma macrocarpa and Coprosma australis. Forest-dominating trees are slower to come in; Corynocarpus most quickly, followed by Beilschmiedia tawa.
E. arborescens has very light wood, rivalling balsa (Ochroma pyramidale) for lightness, and is less dense than cork. The wood was used by Maori for the floats of fishing nets and the like. The large leaves were used to wrap babies in.