This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
A shrub, 3°-10° high, or a small tree, with smooth bark. Twigs, young petioles, leaves and inflorescence somewhat pubescent, becoming glabrate; leaflets 7-9, narrow, 3'-4' long, about 1' wide, long-acuminate, unequally serrate; inflorescence dense, 4'-6' long; flowers yellow, " the centre reddish "; calyx broadly campanulate, its lobes very obtuse; stamens exserted, curved; petals parallel, 5"-6" long; fruit very spiny when young.
Aesculus octandra Marsh. Arb. Am. 4. 1785.
Ae. lutea Wang. Schrift. Nat. Fr. Berl. 8: 133. pl. 6. 1788.
Aesculus flava Ait. Hort. Kew. 1: 494. 1789.
Aesculus hybrida DC. Cat. Hort. Monsp. 75. 1813.
Ae. flava var. purpurascens A. Gray, Man. Ed. 3, 118. 1867.
A large tree, with maximum height of 85°-90° and trunk diameter of 2i°-3°, rarely reduced to a shrub; bark dark brown, scaly. Leaves petioled, the petiole commonly slightly pubescent; leaflets 5, rarely 7, 4'-7' long, 2'-3' wide, oval, glabrous or pubescent on the veins above, more or less pubescent beneath, acuminate at the apex, the lower ones oblique, the others cuneate at the base, all finely serrate; inflorescence rather loose, puberulent; flowers yellow; petals 4, long-clawed, connivent, the 2 upper narrower and longer than the lower; stamens included; fruit smooth even when young.
Aesculus Pavia L. Sp. Pl. 344. 1753.
A shrub, 4°-12° high, rarely a small tree up to 18o high. Leaflets 5-7, stalked, oblong, lanceolate, or obovate, 3'-5' long, 1'-1 1/2' wide, acute or short-acuminate at the apex, all narrowed at the base, finely serrate, nearly glabrous on both sides when mature, shining; inflorescence loose; peduncles 1-3-flowered; flowers bright red-purple, 1'-1 1/2' long; calyx tubular, its lobes short; petals 4, connivent, the upper longer than the lower; stamens about equalling the longer petals; fruit smooth; seeds dark brown.
In rich soil, Virginia to Florida, west to Kentucky, Arkansas and Texas. Fish-poison. April-May.
Aesculus austrina Small, Southern Buckeye, a similar shrub or small tree, has leaves tomentose beneath, and yellow-brown seeds: it inhabits the South-central States, ranging north to Missouri.