What’s special about New Zealand’s native trees and forests?
— Extracted from Field Guide to New Zealand Native Trees by John Dawson
New Zealand’s native trees and forests are unique. They look, smell and feel like no other forests, which is not surprising, as more than 80% of the c. 2400 native species of conifers, flowering plants and ferns in the flora as a whole occur nowhere else in the world. This remarkably high level of endemism is one of the reasons for New Zealand being recognised by Conservation International as a world biodiversity hotspot.
1. Leaflets are alternate on pinnately compound leaves; note that the leaflet at the end is not terminal but attached to the side of the pointed tip of the leaf axis. 2. Two tall tītoki trees with slender trunks and rounded crowns. 3. Mature trunk with buttresses that spread and branch before entering the soil. 4. Attractive foliage. 5. Dark-red branching inflorescence. 6. Female flowers with young capsules; note the curving styles and the non-functional stamens that are devoid of pollen. 7. Flower bud and male flower with stamens releasing white pollen. 8. Close view of female flowers with sterile stamens. 9. Close view of the capsules, spectacular bright-red arils and shiny, black seeds.
Alectryon excelsus |
TĪTOKI SAPINDACEAE
Tītoki, Alectryon excelsus subsp. excelsus, is an attractive, small tree with distinctive furry fruits – when ripe, each splits to expose a single black seed embedded in a layer of bright-red, convoluted tissue. Trees loaded with fruits are a striking sight.
Distribution & Habitat
Found throughout the North Island in coastal and lowland forest, in the north of the South Island, and down to Banks Peninsula in the east and Karamea in the west. Prefers fertile alluvial river flats or sandy plains at low elevations (often growing with tawa), and low forest at exposed coastal sites (often growing with kohekohe). Drought-tolerant when established, but seedlings need shade and moist soil.
Size
Up to c. 10 m tall, and trunk up to 50 cm or more in diameter.
Bark
Smooth, pale grey to almost black.
Foliage & Habit
Leaves are pinnately compound, dark olive-green. The terminal leaflet is often deflected to one side, and the tip of the leaf axis bears a small pointed structure (perhaps the true but undeveloped terminal leaflet). Leaflets are alternate, 3-7 on each side, narrow and mostly pointed at the tip, 5-10 x 2-5 cm. Juvenile leaflets are flat and strongly toothed along the margins; in adults, marginal teeth are absent or few, shallow and blunt, and the leaflet margins are usually downturned. Young leaves and twigs are densely furry with rusty-brown hairs, with hairs on leaf undersides persisting. The crown of the adult tree is broad; the trunk base often has miniature plank or broader buttresses grading into slender roots.
Flowers & Fruits
Male and female flowers are borne on different trees (some bisexual flowers likely). Flowers are furry, tiny, dark red-purple and lacking petals, on elongate branching inflorescences that foliage may partly obscure. Male flowers have a ring of long-stalked stamens around a vestigial ovary; female flowers have short-stalked stamens and often small (‘pollen-less’) anthers. The ovary is furry, with the style bent to one side; it develops into a capsule that is densely furry with rusty-brown hairs, more or less globose with a ridge on top, c. 1 cm in diameter, and with one large, black, shiny seed in a bright-red aril. Capsules mature about a year later, then split to reveal one large seed surrounded by bright-red, fleshy tissue. Flowering is from spring into early summer. Fruits are targeted by native birds, particularly tūi but also introduced blackbirds.
