''Fraxinus uhdei'', commonly known as tropical ash or Shamel ash, is a species of tree native to Mexico and Central America. It is commonly planted as a street tree in Mexico and the southwestern United States. It has also been planted and spread from cultivation in Hawaii, where it is now considered an invasive species. Like other species in the section ''Melioides'', ''Fraxinus uhdei'' is

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

, with male and female flowers produced on separate individuals.

Taxonomy

The tropical ash was originally described as a variety of ''

Fraxinus americana ''Fraxinus americana'', the white ash or American ash, is a species of ''ash tree'' native to eastern and central North America. The species is native to mesophytic hardwood forests from Nova Scotia west to Minnesota, south to northern Florida, ...

'' (white ash) by in 1883 and was separated as a different species in 1907 by Alexander von Lingelsheim. The specific epithet ''uhdei'' refers to Carl Uhde, a German plant collector who explored Mexico in the 1840s. ''Fraxinus uhdei'' is locally known as ''fresno blanco'' in Spanish; other English vernacular names include Hawaiian ash and Mexican ash. The name Shamel ash refers to Archie Shamel, who introduced the trees to California in the 1920s. It is known as Urapan in Colombia, where it was introduced in the 1950s.

Ecology

A dieback caused by a

phytoplasma Phytoplasmas are obligate intracellular parasites of plant phloem tissue and of the insect vectors that are involved in their plant-to-plant transmission. Phytoplasmas were discovered in 1967 by Japanese scientists who termed them mycoplasma-lik ...

was recorded in Colombia and Ecuador in 2004.

References

uhdei Flora of North America Dioecious plants Trees of Central America Trees of Mexico Flora of the Central American pine–oak forests {{Oleaceae-stub