=7.= =Quercus macrocàrpa= Michaux. Bur Oak. Plate 46. Large trees;
branchlets of young trees generally develop corky wings which are
usually absent on mature trees; leaves on petioles 1-2 cm. long, obovate
in outline, generally 1-2.5 dm. long, the margins more or less deeply
cut so that there are usually 7 lobes, sometimes only 5, or as many as 9
or 11, sometimes the sinuses extend to the midrib, giving the leaf a
"skeleton" appearance, the lobes are very irregular in shape and
variously arranged, but often appear as if in pairs, lobes rounded and
ascending, the larger lobes are sometimes somewhat lobed, the three
terminal lobes are usually the largest and considered as a whole would
equal in size one half or more of the entire leaf area, the base of the
leaf is wedge-shape or narrowly rounded; leaves at maturity are dark
green and smooth above, or somewhat pubescent along the midrib, a
gray-green and woolly pubescent beneath; acorns usually solitary,
sometimes in pairs or clusters of three, sessile or on short stalks,
sometimes on stalks as long as 2.5 cm.; nuts very variable in size and
shape, ovoid to oblong, often very much depressed at the apex, 2-3 cm.
long, enclosed from 1/3 to almost their entire length in the cup which
is fringed at the top; cups thick and large, sometimes 4.5 cm. in
diameter; scales tomentose on the back and somewhat tuberculate, blunt
near the base of the cup, but at and near the top of the cup they become
long attenuate and on some trees appear almost bristle like; kernel
sweet.
=Distribution.=--Nova Scotia to Manitoba, south to Georgia and west to
Texas and Wyoming. Found in all parts of Indiana, although we have no
reports from the knob area where no doubt it is only local. It is a tree
of wet woods, low borders of streams, etc., except among the hills of
southern Indiana, it is an occasional tree of the slopes. In favorable
habitats it was a frequent to a common tree. Its most constant
associates are white elm, swamp white and red oak, linn, green and black
ash, shellbark hickory, etc. It is sometimes called mossy-cup oak.
=Remarks.=--Wood and uses similar to that of white oak. In point of
number, size and value it ranks as one of the most valuable trees of the
State. Michaux[39] says: "A tree three miles from Troy, Ohio, was
measured that was fourteen feet and nine inches in diameter six feet
above the ground. The trunk rises about fifty feet without limbs, and
with scarcely a perceptible diminution in size."
=7a.= =Quercus macrocarpa= var. =olivæfórmis= (Michaux filius) Gray.
This variety is distinguished from the typical form by its shallow cup,
and the long oval nut which is often 3 cm. long. The cup is
semi-hemispheric, and encloses the nut for about one-half its length.
Authentic specimens are at hand from Wells County, and it has been
reported from Gibson and Hamilton Counties. No doubt this form has a
wider range.
=8.= =Quercus lyràta= Walter. Overcup Oak. Plate 47. Medium sized trees;
bark generally intermediate between that of the swamp white and bur oak;
leaves on petioles 5-30 mm. long which are generally somewhat reddish
toward the base, 10-20 cm. long, obovate or oblong-obovate, margins very
irregularly divided into 5-9 short or long lobes, ascending and
generally acute, ordinarily the three terminal lobes are the largest,
base of leaves wedge-shape, or narrowly rounded, upper surface at
maturity dark green and smooth, the under surface densely covered with a
thick tomentum to which is added more or less long and single or
fascicled straight hairs; when the leaves are as described on the under
surface they are gray beneath; however, a form occurs which is yellow
green beneath and has little or no tomentum, but is thickly covered with
long single or fascicled straight hairs; acorn single or in pairs, on
stalks generally about 1 cm. long, sometimes the stalks are 3 cm. long,
the stalk lies in a plane at a right angle to the base of the acorn
which is a characteristic of this species; nut depressed-globose, about
1.5 cm. long, generally almost completely enclosed in the cup, or
sometimes enclosed only for about 2/3 its length; cup generally very
thick at the base, gradually becoming thinner at the top, and often it
splits open; scales tomentose on the back, those near the base, thick
and tuberculate on the back and blunt, but those near the top of the cup
are acute or long attenuate; kernel sweet.
=Distribution.=--Maryland to Missouri,[40] and south to Florida and west
to Texas. In Indiana it is found only about river sloughs or deep swamps
in the southwestern counties. At present it is known only from Knox,
Gibson, Posey and Spencer Counties. It was reported by Nieuwland[41] for
Marshall County on the authority of Clark. This specimen was taken
during a survey of Lake Maxinkuckee, and is deposited in the National
Museum. I have had the specimen examined by an authority, who reports
that it is some other species. Its habitat is that of areas that are
inundated much of the winter season. It is so rare that its associates
could not be learned. In one place it grew in a depression lower than a
nearby pin oak, and in another place it grew in a depression in a very
low woods, surrounded by sweet gum, big shell bark hickory, and pin oak.
It is generally found singly in depressions, but it is a common tree on
the low border of the west side of Burnett's pond in Gibson County.
=Remarks.=--Wood and uses similar to that of white oak. In our area it
is usually known as bur oak.
[Illustration: Plate 47.