ENGELMANN—OAKS OF THE UNITED STATES. [389 
l8 
Lea, near Cincinnati, and soon afterwards Dr. S. B. Mead found another 
tree in Hancock Co., Illinois. My specimen, obtained from the first dis¬ 
coverer, has. entire or sinuate or dentate or dentate-lobed leaves, 4-6 
inches long and half as wide, and even in September slightly pubescent 
below; lobes acute and bristle-pointed or quite obtuse; base attenuated 
into a petiole 5-8 lines long; acorns similar to those of coccinea , cup shal¬ 
lower with obtuse scales. The leaves, in Nuttall’s figure have a cordate 
base. Dr. Mead’s tree is similar to Lea’s; leaves apparently more com¬ 
monly entire or undulate-sinuate, 5-7 inches long and half as wide, obtus- 
"ish at base with a petiole i inch long; the pubescence has almost disap¬ 
peared on the lower side of the autumnal leaf; acorns globose, covered 
by the canescent cup. Mr. E. L. Greene sends another specimen from 
Macon Co., Ills.; it is rather more glabrous but otherwise similar, with- 
-out fruit.—The relationship to imbricaria is unquestionable, and it is quite 
probable that among the lobe-leaved Black-oaks we must look to one of 
the forms of coccinea as the other parent. 
2. «^. imbricario-rubra. I found this hybrid two years ago in St. Clair 
Co., Ills., 20 miles from St. Louis, in low, fertile woods where both rubra 
and imbricaria form the bulk of the forest. Growth of the tree and bark 
like rubra ; leaves ample, 4-8 or 9 inches long, 2-6 inches wide, obtuse or 
cordate, rarely acute, at base, the smaller more commonly oblong and en¬ 
tire, the larger ones oval or obovate, entire or sinuate, or with a few broad 
and shallow obtuse or triangular bristle-pointed lobes ; in June still downy 
on the lower surface; petioles inch long, pubescent; fruit unknown. 
3. «^>. fialustri-imbricaria was observed by me a few years ago, 8 miles 
west of St. Louis, in a little dell where imbricaria abounds; falustris^ 
coccinea , and nigra, together with some White-oaks, were near by; the 
tree was only 8 inches in diameter but in full bearing. It had, unfortu¬ 
nately, to give way to a railroad track; but ripe fruit was obtained, which 
to Mr. Meehan of Germantown has furnished fine young plants, completely 
agreeing in character with the parent.—Leaves, as far as I could see, not 
revolute in vernation, pubescent on both sides, but completely denudated 
before the end of May. Full grown leaves broad-lanceolate, mostly acute 
at base, entire or more frequently with a few (sometimes more) coarse, 
triangular-lanceolate, acute, bristle-pointed teeth, glabrous on both sides; 
about 4 inches long, wide, rarely larger; peduncles 3-4 lines long; cup 
moderately deep, turbinate at base, 6-7 lines wjde, 3-4 high; ovate-obtuse 
scales, canescent, with bright brown margins. 
4. imbricario-nigra tridental a, Eng. in Hb.), «^. nigra var. 
tridentata, DC. 1. c. 64. A single tree, rather small, which was soon after¬ 
wards destroyed, was found by me, in the autumn of 1849, on the hills 6 
miles east of St. Louis, in company with both supposed parents and cocci¬ 
nea and rubra, together with some White-oaks. Foliage as well as fruit 
are of such decided character that the origin of this hybrid can scarcely be 
doubted ; the leaves are rather those of imbricaria , with a touch of the pe¬ 
culiar lobation of nigra, and the fruit is more like that of nigra . Leaves 
