Fraxinus

Fraxinus
Fraxinus ornus 1862 illustration[2]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Lamiales
Family:	Oleaceae
Tribe:	Oleeae
Subtribe:	Fraxininae
Genus:	Fraxinus L.[1]
Synonyms[3]
Ornus Boehm. Fraxinoides Medik. Mannaphorus Raf. Calycomelia Kostel. Leptalix Raf. Ornanthes Raf. Samarpses Raf. Aplilia Raf. Meliopsis Rchb. Petlomelia Nieuwl.

Fraxinus (/ˈfræksɪnəs/), commonly called ash, is a genus of plants in the olive and lilac family, Oleaceae,^[4] and comprises 45–65 species of usually medium-to-large trees, most of which are deciduous trees, although some subtropical species are evergreen trees. The genus is widespread throughout much of Europe, Asia, and North America.^{[3][5][6][7][8]}

The leaves are opposite (rarely in whorls of three), and mostly pinnately compound, though simple in a few species. The seeds, popularly known as "keys" or "helicopter seeds", are a type of fruit known as a samara. Some Fraxinus species are dioecious, having male and female flowers on separate plants but sex in ash is expressed as a continuum between male and female individuals, dominated by unisexual trees. With age, ash may change their sexual function from predominantly male and hermaphrodite towards femaleness ^{[clarification needed]};^[9] if grown as an ornamental and both sexes are present, ashes can cause a considerable litter problem with their seeds. Rowans or mountain ashes have leaves and buds superficially similar to those of true ashes, but belong to the unrelated genus Sorbus in the rose family.