Australian Tropical Rainforest Plants - Online edition

Endiandra impressicosta C.K.Allen

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Flowers. © CSIRO
Flower. © Barry Jago
Leaves and Flowers. © CSIRO
Leaves and fruit. © CSIRO
Scale bar 10mm. © CSIRO
Habit, flower, stamen, fruit, seedling. © CSIRO
Flower, bird's-eye view, tepals, anthers and rolled up valves. © CSIRO
Flower, side view, anthers with rolled up valves. © CSIRO
10th leaf stage. © CSIRO
Cotyledon and 1st leaf stage, hypogeal germination. © CSIRO
Cotyledon stage, hypogeal germination. © CSIRO
Cotyledon and 1st leaf stage, hypogeal germination. © CSIRO

Allen, C.K. (1942) Journal of the Arnold Arboretum 23: 151. Type: British New Guinea: Middle Fly River, Lake Daviumbu, Brass 7619 (type, AA) .. Aug. 1936;.

Common name

Sunken Nerve Walnut; Steelbutt


A thin pale brown layer generally visible beneath the subrhytidome layer before the first section of the outer blaze. Blaze usually conspicuously layered and rather hard to cut.


Twigs terete or fluted, glabrous, clothed in straight, appressed, pale brown hairs when very young. Leaf blades about 7.5-14.5 x 4-8 cm, green on the underside, glabrous, very sparsely scattered, straight, appressed, pale brown hairs present on very young leaves. Lateral veins forming loops well inside the blade margin, sometimes tending to form a double series of loops. Young leaves bright red. Midrib depressed on the upper surface. Petioles channelled on the upper surface. Oil dots visible with a lens.


Flowers opening widely, the outer tepals eventually becoming horizontal or reflexed. Tepals about 3.2-4.4 mm long. Staminal glands absent. Staminodes absent.


Fruits ellipsoid, about 45-60 x 30-37 mm. Seed about 38-47 x 20-27 mm. Cotyledons cream.


First pair of leaves narrowly elliptic or ovate, about 75-135 x 25-42 mm, green on the underside. At the tenth leaf stage: leaves narrowly elliptic, glabrous; oil dots small, visible only with a lens. Seed germination time 24 to 42 days.

Distribution and Ecology

Occurs in CYP and NEQ. Altitudinal range from sea level to 500 m. Grows in various rain forests but tends to be more abundant in the drier or more seasonal rain forests. Also occurs in New Guinea.

Natural History & Notes

This species grows large enough to produce millable logs but is seldom utilized for sawn timber. The wood is quite hard and very abrasive to mechanical tools. Wood specific gravity 0.95-1.10. Hyland (1989).

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