Acronychia laevis

hard aspen


Acronychia laevis

J.R.Forst. & G.Forst. 1775

pronounced: ack-roh-NICK-ee-uh LEE-viss

(Rutaceae — the lemon family)

common name: hard aspen

Acronychia is derived from the Greek ακρος (akros), outermost, and ονυξ (onyx), a claw, referring to the petal points; laevis is Latin, used erroneously for levis, smooth, referring to the new shoots and leaves. This is a plant of the monsoon forest and the dry, more seasonal rainforest of eastern Australia, up to about 700 m altitude, from Cape York Peninsula down the coast as far as the Clarence River in NSW. It is also found in New Caledonia and Lord Howe Island.

It grows as a bush or a small tree, up to about 10 m in height. The plant pictured is by The Forts track, and some have also been observed near the Balding Bay track. The leaves, flowers and fruits are all very attractive.

The cylindrical trunk seldom exceeds 30 cm DBH, and has fawn-coloured bark that is fairly smooth, but with some vertical lines and wrinkles. The smaller branches show leaf scars.

The entire leaves are unifoliate, round, ovate or obovate, often blunt or rounded at the tip, opposite, with blades about 2.5 – 9.5 by 1 – 5 cm in size, shiny on both sides. They retain scars showing their evolution from compound leaves to unifoliate. Oil dots are sometimes visible, or may be seen under a hand lens in good light. The lateral veins form loops well inside the margin. The petiole has a channel on the upper surface. There is a distinct joint visible where the petiole joins the leaf blade. The leaves are aromatic when crushed.

The inflorescence is a cyme, from about 1.5 to 7 cm long, with individual flowers, white or cream, about 7 – 10 mm long; the disk is orange; there are 8 stamens, dimorphic, 4 of them long and the other 4 short, in a single whorl with the long and the short stamens alternating. Flowering is usually between November and February, but may be as late as July.

The dark pink, purple or reddish fruit is more-or-less globular drupe, 6 – 8 mm wide, quadrangular towards the base and the apex, with 4 fissures extending from the apex for about half the length of the fruit. It matures usually between June and November. The seeds are reddish brown, about 4 mm long. The Green Catbird eats the fruits. They are edible to humans, but are rather too pungent to be palatable – they have been described as resembling turpentine in flavour.

The tree can be grown in the garden, either from seed or from cuttings, although the latter are sometimes difficult to strike. The tree is said to fruit abundantly every second year.

This is a larval food plant for Papilio aegeus (the Orchard or Citrus Swallowtail Butterfly).

Photographed on The Forts walk, 2014, 2015
Page last updated 4th December 2019