Elaeocarpus hookerianus
Credits
Article from New Trees by John Grimshaw & Ross Bayton
Recommended citation
'Elaeocarpus hookerianus' from the website Trees and Shrubs Online (treesandshrubsonline.
Genus
Common Names
- Pokaka
- Mahimahi
Canopy tree to 12 m; immature plants have divaricate branching. Branchlets slender, striate, initially pubescent. Leaf buds slightly resinous. Leaves evergreen, scattered or grouped towards stem apices, simple, (3–)4–8 × 1–2 cm, obovate, elliptic or oblong, glabrous, venation slightly or strongly prominent on the upper surface, less prominent below, five to nine secondary veins on each side of the midvein, margins crenate to serrate, apex acute or obtuse; petiole 0.5–1.5 cm long, slender, not swollen at either end; foliage of juvenile plants and suckers extremely variable in shape and size. Inflorescences crowded among the leaves or in the axils of fallen leaves, sometimes ramiflorous; racemes 2–4 cm long, bearing (2–)5–12 flowers. Flowers hermaphrodite, 5-merous, to 0.5 cm long; petals split into five to six tapering sections, stamens ~15. Fruit an ellipsoid drupe, 1.1–1.4 × 0.6–0.7 cm; endocarp ridged. Flowering October to January, fruiting November to March (New Zealand). Allan 1961, Coode 1984. Distribution NEW ZEALAND: North and South Is. Habitat Lowland to montane forest. USDA Hardiness Zone 8b–9. Conservation status Not evaluated. Illustration NT318.
The New Zealand flora contains a number of woody species, in several families, in which the young plant has a very curious growth-form, of intertwining or divaricate wiry branchlets, and small hard leaves. Once plants have reached a height of 2–4 m this branching type disappears, and through a series of transitional stages robust branches bearing large broad leaves develop and the individual becomes a normal-looking tree. This syndrome is regarded, by some authorities at least (for example, Atkinson & Greenwood 1989), as an evolutionary strategy to minimise damage by the large, flightless moas that were formerly the largest terrestrial vertebrates and principal browsers in New Zealand. Above their reach the trees could safely develop broader, more succulent foliage, just as Ilex aquifolium produces spineless foliage above browse-height in Europe. A less exciting view is that the juvenile pattern of growth enables more efficient light-capture (Day & Gould 1997, Day 1998), although this seems counter-intuitive.
Elaeocarpus hookerianus is perhaps the most notable of these moa-avoiders, turning from a tangled mass of wiry twigs and small leaves into a tall tree with a dense canopy of broad evergreen leaves. It is valued for both stages in New Zealand, but is very poorly known in the northern hemisphere. It is grown at Tregrehan by New Zealander Tom Hudson, and is doing well there since planting in 1992, forming a straight trunk, with whorls of juvenile growth now giving way to adult foliage at 2–2.5 m height. It may be fractionally hardier than E. dentatus, but not by much, so it too requires a warm sheltered site.