Eucalyptus haemastoma, commonly known as Scribbly Gum, is a medium size Australian eucalypt that can grow up to about 15 m. It belongs to Family Myrtaceae. Eucalyptus haemastoma is found in dry sclerophyll woodland on the coastal plains and hills in the Sydney Region. It grows well in shallow infertile sandy soil.
The bark of the lower part of the tree is dark brown, fibrous-flaky. It is only persistent on lower trunk (a few metres only). After the shedding of the bark in short ribbons, the tree trunk and the branches are smooth with scribbles, white, grey or yellow.
The common name ‘Scribbly Gum’ is a reference to the ‘scribbles’ left on the trunk from the feeding larvae of the scribbly gum moth (Ogmograptis scribula). Eggs are laid between layers of old and new bark. The larvae burrow tunnels into the new bark and, as the old bark falls away, the trails are revealed. The diameters of the tunnels increase as the larvae grow, and the ends of the tracks are where the larvae stopped to pupate.
The adult leaves are stalked, lanceolate to broad-lanceolate or curved, 12 – 17 cm long, 1.5 – 4 cm wide, green or grey-green, glossy. The leaves contains a lot of oil glands.
The flowers are in clusters of 11 or more. Flower buds are ovoid or clavate, 6-8 mm long, 4-5 mm in diameter. Operculum (calyptra or bud cap) is hemispherical or shorter and narrower than hypanthium.
The white flowers appear from mid autumn to late winter (April to August) in Sydney.
The conspicuous part of the flowers are the white filaments of the stamens. The style is green in colour.
The flower does not have petals or sepals, instead it has a hypanthium. The ovary commonly has 4 carpels (4-locular ovary).
After fertilisation, the ovules develop into seeds and the ovary develops into fruit (gum nut).
The fruit is conical or pyriform in shape, 6–9 mm long, 6–9 mm in diameter; the disc is slightly raised; the valves are on rim-level.
I would like to thank Mr Andrew Orme of the National Herbarium of New South Wales (Royal Botanic Garden) for his help in identifying the tree.