Distribution. Rich bottom-lands usually inundated during several weeks of every year; central and western New York and southeastern Ontario, and westward through southern Ohio, southern Michigan, Indiana and Illinois to southeastern Iowa and southeastern Nebraska, through Missouri and Arkansas to southeastern Kansas and northeastern Oklahoma, and southward through eastern Pennsylvania to western West Virginia; in southeastern Tennessee; banks of the Alabama River, Dallas County, Alabama, and in West Feliciana Parish, Louisiana.
× _Carya Nussbaumerii_ Sarg. with leaves like those of _C. laciniosa_, slender branchlets, and large fruit of the shape of that of the Pecan but without sutural wings and white or nearly white nuts, believed to be a hybrid of these species, has been found near Fayetteville, St. Clair County, Illinois, at Mt. Vernon, Posey County, Indiana, near Burlington, Des Moines County, Iowa, and from the neighborhood of Rockville, Bates County, Missouri.
Trees intermediate in character between _C. laciniosa_ and _C. ovata_ growing on the bottoms of the Genessee River at Golah, Munroe County, New York, and believed to be hybrids of these species, are × _C. Dunbarii_ Sarg.
Leaves glandular, resinous, fragrant, 8′—12′ long, with petioles covered like the rachis and the under surface of the leaflets with fascicled hairs, and 5 or 7 oblong-lanceolate to obovate-lanceolate leaflets gradually or abruptly acuminate, mostly equilateral, equally or unequally rounded or cuneate at base, minutely or coarsely serrate, sessile or short-stalked, dark yellow-green and rather lustrous above, lustrous, paler or light orange-colored or brown on the lower surface, the upper leaflets 5′—8′ long and 3′—5′ wide, and two or three times as large as those of the lowest pair. Flowers: staminate in aments 4′—5′ long, with slender light green stems coated with fascicled hairs, pale yellow-green, scurfy-pubescent, with elongated ovate-lanceolate bracts ending in tufts of long pale hairs, and three or four times as long as the calyx-lobes; stamens 4, with oblong bright red hirsute anthers; pistillate in crowded 2—5-flowered spikes, slightly contracted above the middle, coated with pale tomentum, the bract ovate, acute, sometimes ¼′ long, about twice as long as the broadly ovate nearly triangular bractlets and calyx-lobes; stigmas dark red. Fruit ellipsoidal or obovoid, gradually narrowed at the ends, acute at apex, abruptly contracted toward the base, rarely obovoid with a stipe-like base (var. _ficoides_ Sarg.), or ovoid with a long acuminate apex (var. _ovoidea_ Sarg.), pilose or nearly glabrous, dark red-brown, 1½′—2′ long, with a husk about ⅛′ thick splitting to the middle or nearly to the base; nut nearly globose, ellipsoidal, obovoid-oblong or ovoid, narrowed at ends, rounded at base, acute, and sometimes attenuated and long-pointed at apex, much or only slightly compressed, obscurely or prominently 4-ridged, light reddish brown, becoming darker and sometimes red with age, with a very thick hard shell and partitions; in drying often cracking transversely; seed small, sweet, dark brown, and lustrous.