has a strongly beaked operculum, incurved or irregularly bent stamens and narrow lance-shaped juvenile leaves; Eucalyptus camaldulensis subsp. minima Ian Brooker & M.W.McDonald has mature flower buds that are small with a conical operculum long and broad juvenile leaves that are usually covered with a powdery bloom; Eucalyptus camaldulensis subsp. obtusa (Blakely) Ian Brooker & M.W.McDonald has white, powdery bark in some months and mature flower buds with a curved, conical operculum long; Eucalyptus camaldulensis subsp. refulgens Ian Brooker & M.W.McDonald has very glossy green adult leaves with a dense network of veins; Eucalyptus camaldulensis subsp. simulata Ian Brooker & Kleinig. has a horn-shaped operculum long. The specific epithet (camaldulensis) is a reference to a private estate garden (L'Hortus Camaldulensis di Napoli) near the Camaldoli monastery in Naples, where Frederick Dehnhardt was the chief gardener. The type specimen was grown in the gardens from seed presumably collected in 1817 near Condobolin by Allan Cunningham, and was grown there for about one hundred years before being removed in the 1920s. Herbarium specimen of the holotype is deposited in the herbarium of Natural History Museum of Vienna. Although Dehnhardt was the first to formally describe E. camaldulensis, his book was largely unknown to the botanical community. In 1847 Diederich von Schlechtendal gave the species the name Eucalyptus rostrata but the name was illegitimate (a nomen illegitimum) because it had already been applied by Cavanilles to a different species (now known as Eucalyptus robusta). In the 1850s, Ferdinand von Mueller labelled some specimens of river red gum as Eucalyptus longirostris and in 1856 Friedrich Miquel published a description of von Mueller's specimens, formalising the name E. longirostris. Finally in 1934, William Blakely recognised Dehnhardt's priority and the name E. camaldulensis for river red gum was accepted. Northern Territory Aboriginal names for this species are: aper (Alyawarr, Anmatyerr), aper or per (Eastern Arrernte), apere (Kaytetye), aylpele (Pintupi Luritja), itara, ngapiri, pipalya, yitara (Pitjantjatjara) apara, itara, piipalya, (Waramangu), kunjumarra (Warlpiri), kunjumarra and ngapiri (Western Arrernte). Dimilan is the name of this tree in the Miriwoong language of the Kimberley. Distribution and habitat Eucalyptus camaldulensis has the widest natural distribution of any eucalyptus species. It is commonly found along waterways and there are only a few locations where the species is found away from a watercourse. Subspecies acuta is common along rivers from south of Cape York Peninsula in Queensland to the north west slopes and