There are now recognized[14] fifteen species and several varieties of
hickory, all of which grow in the United States east of the Rocky
Mountains. Hickory grows in no other place in the world, except one
species in northern Mexico. The wood of the different species of hickory
is not of equal commercial value, but the wood of the commercial species
heads the list of Indiana woods for strength, toughness and resiliency.
The individuals of the several species vary much in respect to their
bark, size and pubescence of the twigs, number and size of the leaflets,
size and shape of the nuts. No attempt will be made to deal with all of
the extreme forms, and only those reported by Heimlich[15] and
Sargent[16] will be discussed.
Bud scales 4-6, valvate (in pairs), leaflets generally
curved backward.
Leaflets 9-17, generally about 13; nut elongated,
circular in cross-section; kernel sweet 1 C. illinoensis.
Leaflets 5-9, generally 5-7; nut about as broad as
long, compressed in cross-section; kernel bitter 2 C. cordiformis.
Bud scales more than 6, imbricated (not in pairs);
leaflets not curved backward.
Branchlets usually stout; terminal buds large, 7-25 mm.
long; the year's growth usually more or less hairy;
dry husks 4-10 mm. thick.
Prevailing number of leaflets 5 3 C. ovata.
Prevailing number of leaflets more than 5.
Trees of low ground; bark of young trees tight and
light, of older trees scaly, separating into
long thin plates; branchlets usually light
orange color; nuts usually large, compressed,
3-6 cm. long, pointed at base 4 C. laciniosa.
Trees of high ground; bark of young trees tight
and dark, of older trees tight and deeply
furrowed, the thick ridges broken into short
lengths which on very old trees loosen at the
base; branchlets reddish-brown; nuts usually
about half as large as the preceding and
usually with a rounded base 5 C. alba.
Branchlets usually slender; terminal buds small,
5-12 mm. long; the year's growth usually glabrous,
rarely hairy; dried husk 1-2.5 mm. thick.
Branchlets and leaves not covered when they first
appear with rusty-brown pubescence.
Prevailing number of leaflets 5; fruit usually
smooth and tapering at base to a short stem
(fig-like); shell of nut thick, kernel sweet
and astringent 6 C. glabra.
Prevailing number of leaflets generally 7; fruit
usually granular, rarely tapering at the base
to a short stem (fig-like); shell of nut
thin, kernel sweet without astringency 7 C. ovalis.
Branchlets and leaves densely covered when they first
appear with rusty-brown pubescence 8 C. Buckleyi.
=1.= =Carya illinoénsis= (Wangenheim) K. Koch. Pecan. Plate 22. Very
tall slender trees up to 15 dm. in diameter; bark tight, sometimes
becoming scaly on very old trees, fissured, ridges narrow, ashy-brown
tinged with red; twigs at first hairy, becoming smooth or nearly so and
reddish-brown by the end of the season; leaves 3-5 dm. long; leaflets
9-17, ovate to oblong-lanceolate, somewhat curved backward, 7-15 cm.
long, taper-pointed, hairy when they unfold, becoming at maturity smooth
or nearly so, dark green above, and a yellow-green beneath; clusters of
staminate catkins sessile; fruit single or in small clusters, oblong
3.5-6 cm. long, the winged sutures extending to the base, the husk
splitting to below the middle; nut ovoid-oblong, reddish-brown; wood
heavy, hard and not strong.
=Distribution.=--In the Mississippi Valley from Indiana and Iowa south
to Texas. In Indiana it was a native of the southwest part of the State.
It was a common tree in the river bottoms of Point Township of Posey
County, and in the bottoms of the southwest part of Gibson County. It
was found more or less frequently in the bottoms of the Wabash Valley,
as far north as to within four miles of Covington where the author
collected specimens in 1918. It followed the bottoms of the Ohio River
east at least as far as Clark County. Michaux[17] gives it as rare in
the vicinity of Louisville. Victor Lyons of Jeffersonville says that it
was a native to the east part of Survey 29 of the Illinois Grant, and
one tree in the northwest corner of No. 32; and there were nine trees
9-10 dm. in diameter in Floyd County on "Loop Island". A large tree grew
in the bottoms near Bethlehem in Clark County, which is said to have
been a native.
Young[18] says that there are two trees in Jefferson County, one
planted, the other probably native. Coulter[19] says "there are several
trees in the river bottoms."
[Illustration: Plate 22.