''Zieria arborescens'', commonly known as the tree zieria or stinkwood, is a plant in the citrus family Rutaceae and is endemic to eastern

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. It is a bushy shrub or small tree with branches that are ridged and scaly or hairy, at least when young. It has leaves composed of three leaflets and groups of flowers with four white petals, the groups usually shorter than the leaves.

Description

''Zieria arborescens'' is a robust shrub or small tree which grows to a height of . Its branches are ridged where older leaves have fallen and are usually scaly or hairy, at least when young. The leaves are composed of three leaflets which vary in size and shape but are mostly lance-shaped or oblong, long and wide with a stalk long. The edges of the leaves are more or less rolled downwards with the upper surface dark green and glabrous while the lower surface is hairy and pale in colour. Both surfaces of the leaf are dotted with oil glands. The flowers are white or pale pink and are arranged in large groups in upper leaf

axil A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

s, the groups usually shorter than the leaves. There are four more or less hairy, triangular sepal lobes about long. The four

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s are long and slightly hairy. In common with other zierias, there are only four

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s. Flowering occurs from September to November and is followed by a capsule containing seeds which have an ant-attracting

elaiosome Elaiosomes ( grc, ἔλαιον ''élaion'' "oil" + ''sóma'' "body") are fleshy structures that are attached to the seeds of many plant species. The elaiosome is rich in lipids and proteins, and may be variously shaped. Many plants have elaio ...

Taxonomy and naming

''Zieria arborescens'' was first formally described in 1811 by English taxonomist John Sims and the description was published in Botanical Magazine. The original specimen was from

Joseph Banks Sir Joseph Banks, 1st Baronet, (19 June 1820) was an English naturalist, botanist, and patron of the natural sciences. Banks made his name on the 1766 natural-history expedition to Newfoundland and Labrador. He took part in Captain James ...

collection Collection or Collections may refer to: * Cash collection, the function of an accounts receivable department * Collection (church), money donated by the congregation during a church service * Collection agency, agency to collect cash * Collectio ...

in London. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

(''arborescens'') means "tending to a tree-like form". In 2002, James Armstrong described three subspecies in '' Australian Systematic Botany'', and the names are accepted by the Australian Plant Census: *''Zieria arborescens'' Sims subsp. ''arborescens'' is a robust shrub or small tree to , its branchlets slightly ridged, the branchlets usually with short, star-shaped hairs, the petiole and central leaflet densely woolly-hairy, and the peduncles softly-hairy. *''Zieria arborescens'' subsp. ''decurrens'' J.A.Armstr. is a robust shrub to , its branchlets distinctly ridged, the branchlets only covered with star-shaped hairs when young, the lower surface of the petiole and lower surface of the central leaflet softly-hairy or glabrous, and the peduncles with only a few hairs. *''Zieria arborescens'' subsp. ''glabrifolia'' J.A.Armstr. is a robust shrub or small tree to , its branchlets slightly ridged, the branchlets with short, star-shaped hairs, the petiole, central leaflet and peduncles glabrous.

Distribution and habitat

Tree zieria occurs in Queensland, New South Wales, Victoria and Tasmania, growing in wet forest and at the margins of rainforest. Subspecies ''glabrifolia'' only occurs on the New England Tablelands between the

Girraween National Park Girraween National Park is an area of the Granite Belt in the Darling Downs region of Queensland, Australia reserved as a national park. Girraween is known for its spectacular flowers, dramatic landscapes and unique wildlife. Bushwalking and rock ...

in Queensland and Torrington in New South Wales. Subsp. ''decurrens'' is only recorded from near Jervis Bay where it grows in drier eucalyptus areas and features ridged non-warty branches and more hairs on the young branchlets.

References

{{Taxonbar, from=Q8071718 arborescens Sapindales of Australia Flora of New South Wales Flora of Queensland Flora of Victoria (state) Flora of Tasmania Plants described in 1811