Eucalyptus racemosa commonly known as the narrow leaved scribbly gum or snappy gum, is a tree native to eastern Australia around Sydney. It grows in poor sandstone soils in mid to high rainfall areas.
The leaves and the stem
The leaves are long and the length is about five to six times the width, 7 to 15 cm long, 1 to 2.5 cm wide, greyish green on both sides of the leaf.
The bark is smooth with shedding bark of white, grey or yellow. Scribbles often found on the bark. The scribbles were formed by certain insect attack leaving distinctive scribble marks.
The flowers
The showy parts of the flowers are the white filaments of the stamens. Instead of having petals and sepals, a flower has an hypanthium (base) in green colour and an operculum (lid) in white. (The hypanthium and operculum have similar origins as both petals and sepals combined.)
The operculum splits open to release the stamens. Stamens are male reproductive structures made up of anthers and filaments. The anthers produce pollen grains.
The female reproductive structure is called the pistil. It is made up of the stigma, style and ovary. The stigma receives pollen grains. The male nuclei of the pollen grains transferred through the tissue of the style into the ovary. The ovary comprises of 4 carpels. Each carpel contains numerous ovules.
The male nuclei fertilize the female nuclei in the ovule. The ovule develops into a seed. The ovary becomes a fruit (gum nut). The fruit is barrel-shaped, 4 locular, 4-5 mm long, 5-6 mm in diameter. It has 4 valves at rim-level.
Bibliography
http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Eucalyptus~racemosa
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