Quercus stellata
Green Ash (Fraxinus pennsylvanica)

Distribution Map to Right
Counties in blue contain tree

Shape and Distribution
Green ash grows to a height of 60 to 80 feet with a trunk diameter of up to 2 1/2 feet. The crown is rounded, with slender, spreading branches. Green ash is the most widespread of the American ashes. 

It occurs throughout Illinois in bottomland forests and floodplains. Although it occurs naturally in bottomlands, green ash actually tolerates a wide variety of soil conditions and climatic extremes. It is also an attractive tree and is therefore widely planted as an ornamental.

Interesting Facts
Green ash resembles white ash, and the two can be difficult to distinguish. The overall appearance of both trees is similar. One of the best distinguishing features is the color of the lower leaf surfaces. Green ash has leaflets that are green on both surfaces, whereas white ash has distinctly paler lower leaf surfaces. 

Green ash was also formerly recognized as distinctive from red ash, which has hairy leaf stalks and narrow wings along the stalks between leaflets. Presently, the two are lumped together as green ash.

Identifying Features

Green ash bark is light or dark gray with tight, diamond shaped furrows between distinct ridges. 
Twigs are thick, gray to grayish brown, and slightly hairy. 
The buds are rounded and covered with rusty hairs. 
The leaves are opposite and pinnately compound, with 7-9 leaflets. Overall leaf length is 6-10 inches. The leaflets are lance shaped, stalked, and pointed at the tip and are up to 6 inches long and 1 1/2 inches wide. They taper toward the base and are toothed along the edges. The leaflets are yellowish green above and paler and hairy underneath.
Green ash is dioecious. This means that there are separate male and female flowers and that the male and female flowers are borne on separate trees. The flowers appear as branched clusters in April or May, after the leaves have begun to unfold, and are small, purplish, and without petals. 
The fruits are winged, up to 2 1/2 inches long (but usually less) and less than 1/2 inch broad, yellowish brown, with the wing enclosing only a part of the seed at the base. The fruits are borne in clusters around the twig. Songbirds and rodents eat the seeds.
Green ash wood is hard and strong. Tool handles and baseball bats are made from green ash, as well as interior finishing. It is often planted as an ornamental because of its tolerance to a wide range of soil conditions, its beauty, and its resistance to insect pests and disease.