Gossia gonoclada (MYRTACEAE); Square-stemmed myrtle

Austromyrtus gonoclada - foliage & fruit - Brain  2003
Gossia gonoclada
(Prev. known as Austromyrtus gonoclada)

Medium, dense tree to 18m in South east Qld (locally along Oxley Creek) in scrubby, moist riverine and dry rainforest.

Previously Austromyrtus gonoclada. This species is on the Rare and Threatened Plants in Qld list.

Gossia gonoclada is found below the peak flood level on alluvial terraces along permanent watercourses that are subject to some degree of tidal influence in remnant lowland riparian rainforest, situated between the Logan and Brisbane Rivers.

Charles Stuart first discovered Gossia gonoclada in Moggill in the 1850s. Glenn Leiper and Janet Hauser rediscovered the species in December 1986,

A Gossia gonoclada Recovery Team was formed in December 1995. The total number of A. gonoclada in the wild in 2005 had been improved to 285 individuals (from the 73 known in 1995).

New leaves have a pink flush, bark is pale brown, either flaky or scaly. Noticeable are the four raised corners on the angled branchlets and the scent of the crushed leaves when crushed.

The upper leaf surface is glossy and dark green and the lower surface, dull and paler. Small translucent oil glands, distinctive of the Myrtaceae family, occur on both leaf surfaces and produce a distinctive perfume. The flowers are white, 6-9mm in diameter, and occur singly in the leaf axis. The flowers have 4-5 smooth petals. The fruit is a globular, glossy, soft fleshed berry 7-12mm in diameter. The fruit turns black when ripe (usually in January to February) and retains its calyx lobes at the tip.

The species regenerates vegetatively from stem suckers following damage to the main stem. The seed recruitment levels are low, which may be a reflection of habitat disturbance or due to an indirect effect this disturbance has on the species' pollinators.

Gossia gonoclada buds and flowers in late spring (October to November) with the fruits ripening from mid-January to February. Fruits remain viable for only a short period. Trees found in more open habitat appear to produce more viable seeds. Gossia gonoclada produces only a small quantity of fruit in a season.

As the seeds are located within a sweet, soft and fleshy fruit, it is suspected that they are dispersed by animals, particularly birds and bats.

The fruit is edible for humans (Lieper). Silvereyes (Zosterops lateralis) and figbirds (Sphecotheres viridis) have been seen feeding on the fruits. The figbirds consume the entire fruit, whereas the silvereyes peck at the soft flesh causing the seed to drop directly under the trees.

Seed collecting requires permission. The germination period is 8-60 days from the time of sowing, with a success rate ranging from 0-95%. Nursery-grown seedlings can reach 30cm in height within 12 months.

Very attractive tree for the average sized garden. Good windbreak or specimen tree. A good nesting tree for birds.

Recovery Plan
Austromyrtus gonoclada (now Gossia) Angle-stemmed myrtle - In this issue of the newsletter we are featuring Austromyrtus gonoclada as the plant in profile.