Eucalyptus expressa, commonly known as the Wollemi stringybark, is a recentlydiscovered Australian tree species. It has rough, fibrous stringybark on the trunk and larger branches, lance-shaped to curved adult leaves, flower buds in groups of between seven and twenty four and hemispherical to shortened spherical fruit with the valves extending well beyond the rim of the fruit.
Description
Eucalyptus expressa is a tree that typically grows to a height of and has rough, fibrous stringybark on the trunk, and branches wider than. The bark is grey brown, with reddish tinges. Young plants have some leaves arranged in opposite pairs, otherwise alternate, broadly lance-shaped to egg-shaped, glossy green on one surface, paler on the other, long and wide. Adult leaves are arranged alternately, more or less the same glossy green on both sides, lance-shaped to curved, long and wide on a petiole long. The edges of older leaves are scalloped or irregularly toothed and the veinsdiverge at an angle of 30 to 40 degrees to the midrib. The flower buds are arranged in leaf s in groups of between seven and twenty four on a peduncle long, the individual buds on pedicels long. Mature buds are spindle-shaped, long and wide with a conical operculum up to twice as long as the floral cup. The fruit is a woody, hemispherical to shortened spherical capsule, long and wide with the valves protruding above the rim. This species is similar to E. eugenioides but differs in its tall habit, scalloped leaf edges and conspicuously protruding valves in the fruit.
Eucalyptus expressa was first formally described in 2012 by Stephen Bell and Dean Nicolle from a specimen alongside the Putty Road near Bulga and the description was published in the journal Telopea. Before its formal description, it was known as E. sp. aff. eugenioides. The specific epithet is from the Latinexpressus, which means “prominent and clearly exhibited”, and refers to the long, narrow, prominent external valves of the fruit.
A ROTAP rarity rating of 2KC has been proposed for this species. It is poorly known and suspected of being at risk, occurring in a range of less than, although at least partially conserved in a national park.
