Ash Keys

1.	Twigs with 4 angles or ridges [square in cross-section], often winged; flowers perfect; reported only from Lee & Des Moines counties in SE Iowa.	Fraxinus quadrangulata Blue Ash
1.	Twigs round in cross-section or nearly so; flowers unisexual; trees dioecious [bearing either male or female flowers, but not both].	[2]

2.	Lateral leaflets sessile [petiolule lacking]; wing of fruit extending to the base of seed body, body of seed strongly flattened.	Fraxinus nigra Black Ash
2.	Lateral leaflets stalked [at least lower leaflets w/a short petiolule]; wing of fruit terminal or extending ≤ 1/2 way to the base of seed body, body of seed distinctly round in cross section.	[3]

3.	Lower leaflet surface whitened and minutely "pimply" [papillose], stalk of leaflet commonly > 0.5 cm; wing of fruit extending ± over the apical 1/3 of the seed proper; typically an upland tree.	Fraxinus americana White Ash
3.	Lower leaflet surface green and lacking minutely "pimply" [papillose] texture, stalk of leaflet typically < 0.5 cm; wing of fruit extending along the apical 1/2 of the seed proper; typically a bottomland tree.	Fraxinus pennsylvanica Red Ash

Above identification key modified from: Pohl, R. W. 1975. Keys to Iowa vascular plants. Kendall/Hunt Publishing Co., Dubuque, IA. References used for construction of this key. Ash distribution maps.

"Outside of a dog, a book is a man's best friend. Inside of a dog it's too dark to read."
--- Groucho Marx