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Zieria covenyi

Coveny’s Zieria

Family: Rutaceae

An upright shrub, potentially to 2 metres high (but often much smaller), reportedly growing from root suckers.

It is known to only occur in two locations, at Narrow Neck Peninsula, within Blue Mountains National Park, south-west of Katoomba; and at Breakfast Creek in the Megalong Valley in New South Wales.

It is a listed threatened species.

It grows in open dry sclerophyll woodland and forest, on sandy soils derived from sandstone, on east and south-facing slopes and on ridges.

Branches have star-shaped (stellate) hairs.

Zieria spp. have leaves arranged in opposite pairs, compound with three leaflets (tri-foliolate) or one leaflet (uni-foliolate). When tri-foliolate, 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, dark green above and grey-green below, and dotted with oil glands, with the leaflets oblong to elliptic or ovate, to 35 mm long and to 10 mm wide.

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 to pale pink, to 13 mm in diameter, arranged in clusters of between 3 and 25 in leaf axils, with clusters about the same length as the leaves, occurring from October to December.

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, fruit has historically never been observed. However, it has been observed recently in propagated plants.

In the garden

This is a listed threatened species in the wild and does not have a history of cultivation. However, plants have been propagated and planted at several schools in the Blue Mountains as part of Saving our Species efforts. It may be available for sale at select native nurseries (such as Mt Annan Botanic Gardens).

Many Zieria make interesting garden plants and deserve a place in gardens. They are a member of the Rutaceae family which include the genera Boronia, Philotheca and Crowea, all of which can be challenging to grow.

This species grows on shallow sandy soils derived from sandstone.

This species is reported to have sterile pollen and produces very little fruit or seed. It reproduces vegetatively by root suckering. This species probably arose following hybridisation between two other Zieria taxa.

Propagation

Plants have been propagated from cuttings at Mt Annan Botanic Gardens.

Other information

Zieria is a genus strongly odoriferous soft-woody shrubs, or small trees, with over 40 species described, all of which are endemic to Australia except for one species which is found in New Caledonia. They occur in all Australian states except Western Australia but the genus is under review and a number of species are yet to be described or the description published.

Zieria are similar to the better known genus Boronia but can be distinguished by the number of stamens in the flowers – four and eight in Boronia.

Most Zieria would die in a bushfire and regenerate from seeds. Suckering from roots may be possible.

This species is likely to be fire tolerant and able to resprout from root suckers.

Zierianamed in honour of Jan Zier (d. 1793), by Sir James E. Smith. Zier was a Polish botanist and cryptogam (ferns, mosses, lichen and fungi) specialist, for which there is little information online. He assisted Jacob Friedrich Ehrhart, the Director of the Botanical Garden of Hannover.

covenyi  – named in honour of Australian herbarium collector, Robert George (Bob) Coveny (b. 1943) who, with James Armstrong, collected the type specimen. Bob has collected approximately 20,000 plant specimens in his lifetime, across Australia.

This species is listed as being threatened with extinction in the wild, at both the State and Commonwealth level, with the category of Endangered.

Wikipedia – Zieria and Zieria covenyi profile pages

https://en.wikipedia.org/wiki/Zieria

https://en.wikipedia.org/wiki/Zieria_covenyi

NSW Office of Environment and Heritage – Zieria covenyi profile pages

https://www.environment.nsw.gov.au/threatenedSpeciesApp/profile.aspx?id=10853

NSW Flora Online (PlantNET) – Zieria covenyi profile page

https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Zieria~covenyi

Blue Mountains Gazette – Blackheath students are helping to keep a rare species alive

https://www.bluemountainsgazette.com.au/story/6038495/students-saving-rare-plant/

By Jeff Howes, edited Dan Clarke