Swamp mahogany

Eucalyptus robusta grows as a tree to around 20–30 metres (70–100 ft) tall, with a trunk up to 1 metre (3.3 feet) in diameter at breast height (dbh). The trunk and branches are covered with thick red-brown bark, which has a spongy feel and is stringy—peeling in longitudinal strips. The long irregular branches spread laterally, and form a dense canopy with the broad green leaves. Arranged alternately along the stems, these measure 10–16 centimetres (3.9–6.3 inches) long by 2.7 to 4.5 cm (1.1 to 1.8 in) wide. The white or cream flowers are clustered in inflorescences of from seven to 13 flowers. The flowers appear anywhere from March to September, and peak over May and June. The buds measure 2 by 0.8 cm (0.79 by 0.31 in) wide and are distinctive in that the operculum has a prominent long beak, making them fusiform (spindle-shaped). The woody fruits ripen by May to October.
The bangalay (E. botryoides) is similar in appearance, but its flower buds are smaller with a conical operculum and only grow in groups of seven. The fruits are smaller and sessile, rather than on stalks