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The new site offers several benefits over the existing website, including real coordinate mapping, giving a clearer view of the density of documentation as well as more precision about plant distributions and their link to landforms. We will also have the ability to update species pages more regularly, both in terms of new collections and as more existing Michigan specimens are georeferenced. In addition, we have a better photo display, and offer indented keys.

Fraxinus quadrangulata Michx.
Common Name: BLUE ASH
Coefficient of Conservatism: 8
Coefficient of Wetness: 3
Wetness Index: FACU
Physiognomy: Nt Tree

Fraxinus quadrangulata twig B. S. Walters twig

Deciduous forests, usually on floodplains, occasionally on uplands.

As in F. nigra, the calyx is lacking (or early deciduous) and the fruit is strongly flattened, but the lateral leaflets have short petiolules. Besides the unique winged twigs, larger trees often have distinctive downturned lower branches that may persist even when dead on fully mature trees.

This species shows much resistance to the emerald ash borer, and trees are often damaged but recover or at least continue to survive. It has thus not shown the extreme decline in numbers of larger trees like all other ash in Michigan. 


Allegan County
Barry County
Berrien County
Clinton County
Genesee County
Hillsdale County
Ingham County
Ionia County
Kalamazoo County
Kent County
Lenawee County
Macomb County
Oakland County
Shiawassee County
St. Clair County
Washtenaw County
Wayne County


MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. January 30, 2023.