"In the shape of the fruit and in the thickness of its involucre this tree is of four distinct forms; in all of them the involucre splits freely to the base, or nearly to the base, the shell of the nut is thin and the seed, although small, is sweet and edible. The extremes of these forms are very distinct, but there are forms which are intermediate between them, so that it is difficult to decide sometimes to which of the forms these intermediate forms should be referred. The first of these forms, as the fruit agrees with Wangenheim's figure, must be considered the type of the species. The fruit is oval, narrowed and rounded at the base, acute at the apex, usually from 2.5-3 cm. long and about 1.5 cm. in diameter. The involucre is from 2-2.5 mm. thick and occasionally one of the sutures remains closed. The nut is oblong, slightly flattened, rounded at the base, acute or acuminate and four-angled at the apex, the ridges extending for one-third or rarely for one-half of its length, from 2-2.5 cm. long and about 1.5 cm. in diameter. The shell is usually about 1 mm. thick." "The type of this species and its varieties have glabrous or rarely slightly pubescent leaves, with usually 7 thin leaflets."
7a. Carya ovalis variety obcordàta (Muhlenberg) Sargent. "The fruit varies from subglobose to short-oblong or to slightly obovate, showing a tendency to pass into that of the other varieties of the species. It varies from 2-3 cm. in diameter, and the involucre, which is from 2-5 mm. thick, splits freely to the base or nearly to the base by narrowly winged sutures, one of them rarely extending only to the middle of the fruit. The nut is usually much compressed, often broadest above the middle, slightly angled sometimes to below the middle, rounded at the base and much compressed, often broadest above the middle, slightly angled sometimes to below the middle, rounded at the base and rounded and often more or less obcordate at the apex."
7b. Carya ovalis variety odoràta (Marshall) Sargent. "The name may have been given by Marshall to this variety on account of the strong resinous odor of the inner surface of the fresh involucre of the fruit, which I have not noticed in that of the other forms. The fruit is subglobose or sometimes slightly longer than broad, flattened and usually from 1.3-1.5 cm. in diameter. The involucre varies from 1-1.5 mm. in thickness and splits freely to the base by distinctly winged sutures. The nut is rounded or acute at the base with a short point, rounded at the apex, very slightly or not at all ridged, pale colored, from 1.2-1.5 cm. long and wide and from 1-1.2 cm. thick."
7c. Carya ovalis variety obovàlis Sargent. "In the fourth form the fruit is more or less obovate, about 2.5 cm. long and 2 cm. in diameter, and the involucre varies from 2-4 mm. in thickness. The nut is much compressed, pointed or rounded at the apex, rounded at the base, usually about 2 cm. long, nearly as broad and about 1.5 cm. thick." "The fruit resembles in shape that of Carya glabra, but the involucre is thicker and splits easily to the base or nearly to the base."
7d. Carya ovalis variety obcordàta, f. vestita Sargent. Bot. Gaz. 66:246:1918. This is a form described from a specimen collected by the author on the border of Dan's Pond in Knox County. It differs from "the variety obcordata in the thick tomentose covering of the branchlets during their first year. The leaves of this form are slightly pubescent in the autumn on the under surface of the midribs. Although the nuts are more compressed than those of the ordinary forms of var. obcordata, the fruit is of that variety. The branchlets are unusually stout for a form of Carya ovalis and are covered with rusty tomentum during their first year and are more or less pubescent in their second and third seasons."
Distribution.—Western New York west to Illinois and south to North Carolina, Georgia, Alabama, Mississippi, Arkansas and Missouri. The species is found in all parts of the State, although the distribution of the varieties has not been worked out. The habitat of this species is high ground, and only rarely is it found in low ground. It prefers hills, slopes, base of the terraces of streams, and in the northern part of the State gravelly ridges and sandy soil. In all of its range it is usually associated with white and black oak. It is infrequent in the southern part of the State but north of the Wabash River it becomes more frequent and in some places it becomes common to very common. It is a common tree in Wells County north of the Wabash River and in the northern part of Lagrange County, and in both places a wide range of forms occur, some of which are not covered by the preceding description. No one of our trees offers a better opportunity for intensive study than this hickory.
Remarks.—Text books call this species the small-fruited hickory. It is not commonly distinguished from the other hickories, but in Wells County where it is common the boys call it "Ladies' Hickory."
8. Carya Búckleyi variety arkansàna Sargent.[27] [Plate 29.] Medium sized trees, bark tight, dark, deeply furrowed; mature twigs more or less pubescent, reddish brown; terminal buds ovoid, about 8 mm. long, thickly covered with yellow scales, and more or less pubescent; leaves 2-3.5 dm. long, rachis permanently pubescent; leaflets 5-7, prevailing number 7, lanceolate, terminal one about 15 cm. long, tawny pubescent on unfolding, more or less glabrous at maturity; fruit ellipsoid to slightly obovoid, very aromatic, about 3.5-4 cm. long, covered with yellow scales; husk usually splitting to below the middle, 3-4 mm. thick; nut oblong to slightly obovoid, 3-3.5 cm. long, scarcely compressed, rounded at each end, the four ridges faint except at the apex; shell thick, about 2 mm. at the thinnest point; kernel sweet; wood same as the white hickory which it most closely resembles.
Distribution.—Southwestern Indiana, south in the Mississippi Valley to Louisiana and Texas. Known in Indiana only from one tree in Knox County on the sand ridge on the east side of what was formerly a cypress swamp, about two miles north of Decker. The soil is the Knox sand. It is associated with black and black jack oaks.