The woods resemble one another in that they are soft, straight-grained, easily worked, and decay rapidly when exposed. They are employed to some extent in woodenware, artificial limbs, and paper-making. The trees may be known by their round prickly pods, containing smooth chestnut-colored bitter nuts. The leaves of the buckeye are arranged in groups of five, while those of the horse chestnut are in groups of seven. The horse chestnut produces showy spotted flowers. There are thirteen species of this genus, eight of which are North American. The name "horse chestnut" may refer ironically to the coarse nuts, or may arise from the fact that they are occasionally eaten by cattle, or from a horseshoe marking seen on young twigs. _Hippocastanum_ is from _hippos_, a horse, and _castanea_, a chestnut. The name buckeye refers to the appearance of the brown nut through the paler husk partly separated when ripe, suggesting the eye of the common deer. [p097] [Illustration: PLATE 20. HORSE CHESTNUT (_Æsculus hippocastanum_).] OHIO BUCKEYE, FETID BUCKEYE. _Æsculus glabra Willd._ Nomenclature. (Sudworth.) Buckeye, Ohio Buckeye (local and common names). Fetid Buckeye (W. Va.). Stinking Buckeye (Ala., Ark.). American Horse Chestnut (Pa.). Locality. Ohio River basin to Alabama, portions of Iowa, Kansas, and Indian Territory. Features of Tree. Twenty-five to forty-five feet in height. One to one and one-half feet in diameter. Yellowish-white flower, succeeded by round prickly pod or fruit. Color, Appearance, or Grain of Wood. Heartwood white, sapwood a little darker, close-grained, frequent dark lines of decay. Structural Qualities of Wood. Weak, light, soft, hard to split. Representative Uses of Wood. Artificial limbs, woodenware, paper-pulp, rarely lumber. Weight of Seasoned Wood in Pounds per Cubic Foot. 28. Modulus of Elasticity. 910,000. Modulus of Rupture. 7000. Remarks. FOOTNOTE The nearly similar horse chestnut (_A. hippocastanum_) is forty to fifty feet or more in height and two to four feet in diameter. The light, weak wood is seldom used. The name horse may be applied to the coarse nuts ironically, or may refer to their occasional use by cattle, or a horseshoe marking seen on young twigs. [p098] BUCKEYE, SWEET BUCKEYE. _Æsculus octandra Marsh._ _Æsculus flava Ait._ Nomenclature. (Sudworth.) Buckeye (N. C., S. C., Ala., Miss., La., Tex., Ky.). Sweet Buckeye (W. Va., Miss., Tex., Mo., Ind.). Yellow Buckeye (S. C., Ala.). Large Buckeye, Big Buckeye (Tex., Tenn.). Locality. Alleghany Mountains, Pennsylvania to Georgia, westward intermittently to Iowa and Texas. Features of Tree. Forty to seventy feet in height, one to three feet in diameter, sometimes low shrub. Large mahogany-colored seed. Color, Appearance, and Grain of Wood. Heartwood, creamy white, sapwood similar, compact structure, close-grained, difficult to split. Representative Uses of Wood.