704 TREES OF NOKTH AMERICA. 



yellow in the autumn before falling. Flowers pale yellow-green, mostly unilateral, %'-l? r 

 long or more than twice as long as the pedicels, appearing in April and May in clusters 5'-6' 

 long and 2'-3' wide, and more or less densely covered with pubescence, with short usually 4- 

 6-flowered branches; calyx campanulate; petals nearly equal, puberulous, the thin limb about 

 twice as long as the claw, in the lateral pair broad-ovate or oblong, and in the superior pair 

 oblong-spatulate, much narrower, sometimes marked with red stripes; stamens usually 7, 

 with long exserted curved pubescent filaments and orange-colored slightly hairy anthers; 

 ovary pubescent, covered with long slender deciduous prickles thickened and tubercle- 

 like at base. Fruit on a stout stem ^'-1' long, ovoid or irregularly obovoid, pale brown, l'-2' 

 long, with thin or sometimes thick valves, roughened by the enlarged persistent bases of 

 the prickles of the ovary; seeds l'-l' broad. 



A tree, occasionally 70 high, with a trunk rarely 2 in diameter, small spreading branches, 

 and branchlets orange-brown and covered at first with short fine pubescence, soon gla- 

 brous, reddish brown, and marked by scattered orange-colored lenticels; usually much 

 smaller, and rarely more than 30 high. Winter-buds f long, acuminate, with thin 

 nearly triangular pale brown scales, the outer bright red on the inner surface toward the 

 base, those of the inner pair strap-shaped, prominently keeled on the back, minutely apicu- 

 late and slightly ciliate along the margins, and at maturity l'-2' long and bright yellow. 

 Bark of young stems and of the branches dark brown and scaly, becoming on old trees f ' 

 thick, ashy gray, densely furrowed, and broken into thick plates roughened on the sur- 

 face by numerous small scales. Wood light, soft, close-grained, not strong, often blemished 

 by dark lines of decay, nearly white, with thin dark-colored sapwood of 10-12 layers of 

 annual growth; used in the manufacture of artificial limbs, wooden ware, wooden hats, and 

 paper pulp; occasionally sawed into lumber. An extract of the bark has been used as an 

 irritant of the cerebro-spinal system. 



Distribution. River-bottoms and the banks of streams in rich moist soil ; western slopes 

 of the Alleghany Mountains, western and southwestern Pennsylvania to northern Alabama, 

 and westward to central and southern Iowa, southeastern Nebraska, northern and central 

 Missouri and northeastern Kansas; nowhere abundant; most common and of its largest 

 size in the valley of the Tennessee River in Tennessee and northern Alabama. 



A shrubby form (var. micrantha Sarg.) with flowers not more than -|' long near Fulton, 

 Hempstead County, Arkansas. In southern Missouri, Arkansas and probably Oklahoma 

 Aesculus glabra is replaced by the var. leucodermis Sarg. with glabrous leaves pale green or 

 glaucescent below. A tree occasionally 60 high, well distinguished from the type by the 

 smooth pale nearly white bark of the trunk and large branches, becoming on old trunks 

 light brown and separating into oblong flakes, and by its later flowers; the var. pallida in 

 Iowa, Missouri and Arkansas; the var. Buckleyi in Jackson County, Missouri, eastern 

 Kansas, Ohio and Mississippi. 



The Ohio Buckeye is occasionally cultivated as an ornamental plant in the eastern 

 United States and Europe; hardy as far north as eastern Massachusetts. 



X Aesculus Bushii Schn., probably a hybrid of Aesculus discolor var. mollis Sarg. and 

 Aesculus glabra var. leucodermis Sarg., has been found in the neighborhood of Fulton, Hemp- 

 stead County, Arkansas; and what is evidently a hybrid of Aesculus discolor var. mollis and 

 the typical form of Aesculus glabra occurs near Starkville, Oktibbeha County, Mississippi 



X Aesculus mississippiensis Sarg., a probable hybrid between Aesculus glabra and Aescu- 

 lus Pavia with characters intermediate between those of its supposed parents, occurs near 

 Brookville, Noxubee County, Mississippi. The mingling of a species of the Octandrse 

 and of the Eupavise in these hybrids of Aesculus is shown by the presence of both hairs 

 and glands on the margins of the petals. 



2. Aesculus octandra Marsh. Sweet Buckeye. 



Leaves with slender or slightly pubescent petioles 4 '-6' long, and 5-7 elliptic or obovate- 

 oblong leaflets, acuminate and usually abruptly long-pointed at apex, gradually narrowed 

 and cuneate at base, sharply and equally serrate, glabrous above except on the midrib and 



