Which genus includes many trees commonly called eucalyptus or gum trees?

The genus that includes many trees commonly called eucalyptus or gum trees is Eucalyptus.

Eucalyptus is a large genus in the myrtle family, Myrtaceae, with most species native to Australia. Its members include tall forest trees, smaller mallees, and a few shrubs. They are recognized by distinctive flower buds capped by an operculum, showy clusters of stamens, and woody fruits often called gumnuts.

The common-language picture is slightly broader than the botanical answer. In Australia, “eucalypt” or “gum tree” can also refer to related genera such as Corymbia and Angophora. Nevertheless, Eucalyptus is by far the best-known and largest genus associated with those names, so the stored answer is the canonical quiz response.

The generic name was coined by Charles Louis L’Héritier de Brutelle and published in 1789. It comes from Greek roots meaning “well covered,” referring to the cap protecting the developing flower. Eucalypts are widely planted beyond Australia for timber, pulp, oils, shade, and honey, although some introduced stands can intensify fire hazards.