Zieria arborescens

A robust large shrub, growing to potentially 10 metres tall.

It occurs from just into the south-east of Queensland, growing south in disjunct patches on the coast and tablelands of New South Wales with populations at areas such as north-east of Glen Innes, Laurieton, Olney and Watagans State Forest (west of the central coast), Mt Wilson, between Robertson and Kiama, Jervis Bay and then in small disjunct patches down to the south coast and inland of NSW, into south-eastern and southern-central Victoria, and into Tasmania where it is very common.

It grows in wet forest and at the margins of rainforest, usually on enriched soils.

Branches have prominent ridges where older leaves have fallen and are usually hairy when young.

Zieria spp. have leaves arranged in opposite pairs, compound with three leaflets (tri-foliolate) or one leaflet (uni-foliolate). When trifoliolate, the leaflets are often similar in shape with the middle leaflet often larger, and with leaves usually strongly odorous, green to grey-green.

In this species leaves are trifoliolate, with leaflets varying in size and shape but mostly lanceolate to oblong, to 90 mm long and to 15 mm wide with a stalk to 30 mm long. Both surfaces of the leaf are dotted with oil glands with a strong odour that many find unpleasant.

Zieria spp. have flowers arranged in groups (cymose clusters) in the leaf axils and have four sepals joined at the base and four petals, alternating with the sepals. There are four stamens and four fused carpels.
In this species flowers are white or pale pink and are arranged in large clusters in upper leaf axils, the clusters usually shorter than the leaves, petals are to 7 mm long, with flowering occurring from September to November.

Zieria have a fruit described as a schizocarp-capsule which splits into segments called cocci (singular coccus). Fruit generally have four cocci, each containing one or two seeds. In this species, the capsule contains four cocci, each of which have an ant-attracting elaiosome — a structure on the surface of a seed that secretes and stores oil.