Plants trees and shrubs, heterophyllous, leaves of seedlings, juvenile, intermediate, and adults leaves usually differing in shape and sometimes arrangement. Adultleaves usally alternate. Inflorescences usually umbel-like, with 3 0r more flowers, rarely flowers solitary; flowers with a woody hypanthium; calyces and corollas united, forming an operculum that falls of at anthesis; stamens many; ovaries 2-7-celled, with axile placentation. Fruits capsules enclosed by the woody anthoecia; seeds several to many.
Eucalyptus includes over 500 species, the vast majority of which are native to Australia but some extending to the Philippines and Malaysia. Many species have been plants in warmer parts of the would for timber, firewood, oil production, or as ornamental species. The species in the key are those considered to be those generally found in Somaliland and Somalia. There may be more present in the two countries.