Elaeocarpus arnhemicus, commonly known as elaeocarpus, blue plum, bony quandong or Arnhem Land quandong, is species of flowering plant in the family Elaeocarpaceae and is native to northern Australia, New Guinea, Timor and certain other islands in the Indonesian Archipelago. It is a tree with narrow elliptic to lance-shaped or egg-shaped leaves with serrated edges, racemes of white or cream-coloured flowers and metallic blue fruit.

Description

Elaeocarpus arnhemicus is a tree. Although it was once believed to often grow as a shrub and only grow to a height of 15m (49ft) with a DBH of up to 30cm (12in), it is now known that it can become a much larger plant, to 40m (130ft) high.

The leaves are narrow elliptic to lance-shaped or egg-shaped, 50–122mm (2.0–4.8in) long and 20–53mm (0.79–2.09in) wide with serrations on the edges, on a petiole 3–15mm (0.12–0.59in) long. The flowers are arranged in racemes up to 60mm (2.4in) long, each flower on a pedicel up to 5mm (0.20in) long. The sepals are ovate, 2.5–3mm (0.098–0.118in) long and 1.4–2mm (0.055–0.079in) wide. The petals are obovate, white or cream-coloured, 2.7–4.2mm (0.11–0.17in) long and 1.5–3.1mm (0.059–0.122in) wide, the tip with 7-12 linear lobes. Both the petals and sepals are usually only 3–3.5mm (0.12–0.14in) long. There are between fifteen and eighteen, sometimes up to twenty, stamens and the style is 1.2–2mm (0.047–0.079in) long and glabrous. Flowering occurs from January to July and the fruit is an elliptical, metallic blue drupe 8.2–16.5mm (0.32–0.65in) long and 6.5–12.5mm (0.26–0.49in) wide.

This species is best identified among other Elaeocarpus species when in flower.

Taxonomy and naming

Elaeocarpus arnhemicus was first formally described in 1868 by Ferdinand von Mueller in his book Fragmenta Phytographiae Australiae.

It is placed in the Fissipetalum group of Elaeocarpus species.

Distribution and habitat

Blue plum grows in riparian rainforest and some other habitats in the northern part of the Northern Territory, Cape York Peninsula, north-east Queensland and New Guinea at altitudes up to 500m (1,600ft) above sea level. In 2001 the known range was expanded to Java, Timor, Flores, Sumba and Sulawesi. After receiving some new specimens, M. J. E. Coode, expert Elaeocarpus taxonomist, realised that a few old specimens from two collection localities that he and his colleague Raymond Weibel had never been able to identify, were actually E. arnhemicus, considerably expanding its range.

See also