Eucalyptus deuaensis, the Mongamulla Mallee is a eucalyptus of south eastern Australia. A threatened species, with a rarity rating of 2RCit on ROTAP. The original specimen was collected in 1984, at the only known population, near Mongamulla Mountain, in Deua National Park, west of Moruya. Found at altitudes between 500 and 800 metres above sea level on infertile shallow soil, based on rhyolite.The Mongamulla Mallee is a mallee or small tree to 5 metres tall. Old bark is grey or a pale reddish brown. After the shedding of the old bark, the newer bark underneath is white or yellowish.