August in the hills with Chris Horne and Michele Dickson
Elaeocarpus hookerianus, pōkaka,
Origin of the botanical name
Elaeocarpus comes from the Greek words for ‘olive-tree’ and ‘fruit’; hookerianus comes from Sir William Jackson Hooker (1785-1865), Director, Royal Botanic Gardens, Kew, or his son, Sir Joseph Dalton Hooker (1817-1911), naturalist on the “Erebus” during the British Antarctic Expedition and author of Flora Novaezelandiae. The only other member of the Elaeocarpus genus in New Zealand is hīnau, E. dentatus - see The Tramper February 2013.
Distribution and habitat
Pōkaka is endemic to New Zealand. Look for it in lowland to montane forests on Te Ika a Maui/North Island from Kaitaia south, on Te Waipounamu/South Island and on Rakiura/Stewart Island.
Pōkaka is a canopy tree up to about 12 m tall. The trunk is up to 1 m diameter with pale, rough bark with narrow longitudinal fissures. The leaves are 3-11 cm long x 1-3 cm wide. They are alternate, leathery, lance-shaped with blunt or sharply pointed ends. Pōkaka is sometimes host to pirinoa / small-flowered mistletoe / Ileostylus micrantus. Young plants have a remarkable bushy form with flexible entangled branchlets forming a dense mass. This habit is called “divaricating”. The tiny, long-persisting juvenile leaves have many forms, from egg-shaped up to 12 mm long with the narrow end at the base, to very narrow with parallel edges, up to 5 cm long x 6 mm wide. They range in colour from green to brown to white. On adult trees look for ‘reversion’ shoots bearing leaves with the linear juvenile form. Divarication is common in New Zealand plants – about 60 species of trees and shrubs display this growth form. Few species overseas are divaricate.
Pōkaka flowers from October to January. The drooping, white flowers, 4-6 mm diameter, have deep longitudinal incisions. The oval, purple-black stone fruit (a drupe), about 8 mm long, appear from November to March. Distribution of seeds is by birds.
Māori used pōkaka to produce a mordant to make a black dye.
Where can you find pōkaka?
Look for it in Ōtari-Wilton’s Bush, East Harbour Regional Park, Porirua Scenic Reserve and the Tararua, Remutaka Aorangi and Akatarawa ranges. If you see a tree with leaves like a blend of pōkaka and hīnau, you may have found a hybrid.