Canopy-tree to 30 m; lfls 5, dark bluish-green, ±drooping, oblanceolate to narrowly obovate, 10-15 cm, finely serrate, pubescent beneath when young; infls 1-1.5 dm, the pedicels and cal beset with small stipitate glands; cal tubular, 7-16 mm, shallowly lobed; pet 4, dull yellow to sometimes tawny or purplish or reddish, villous on the margin, the lateral ones 1.5-2.5 cm, with broadly elliptic blade and exsert claw, the upper 2-3 cm, with a much smaller blade on a long claw; stamens 7 or 8, equaling or shorter than the pet; fr smooth, 5-8 cm thick; 2n=40. Rich moist woods; sw. Pa. and s. O. to s. Ill., s. to n. Ga. and n. Ala. May, June. (A. octandra) Hybridizes with no. 2.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Infrequent on wooded slopes near the Ohio River from Dearborn to Crawford Counties. Phinney's report for Delaware and Jay Counties was an error. The flowers vary in color from deep yellow to purple or reddish purple. This variation, added to the fact that the species begins flowering when it is shrublike and ultimately grows to be a very large forest tree, has led authors to describe several species and forms. A purple flowered form was reported by Young' for Jefferson County under the name of Aesculus flava var. purpurascens. This color form is now known as Aesculus octandra f. virginica (Sarg.) Fern. (Rhodora 39: 318. 1937.)