ENGHLMANN OAKS OF THE UNITED STATES. 539 



The Oaks of the United States. 



(Continued from p. 400.) 



^. Catesb<Biy^ laurtfolia, a late discovery of Dr. MelHchamp, is found 

 in the same neighborhood, 'in the cove with laurtfolia ?ir\dfalcata, a tree 

 50 feet high, bark very much like that of the former." — Leaves lanceolate 

 to ovate in outline, the uppermost narrower and entire, the lower wider, 

 and generally near the middle with i or 2, rarely with more, divaricate 

 or even falcate, acuminate lobes, coriaceous, strongly reticulate above, 

 persistent through the greater part of winter, 3-4^ inches long, |-2 or 2^ 

 inches wide, petioles ^inch long; youngest leaves imbricate in bud, slightly 

 downy below, densely fulvous-glandular above, soon glabrate ; leav.es of 

 vigorous shoots much larger and more lobed ; acorn subglobose, 7-7^ lines 

 w^ide, about half immersed in a hemispherical, turbinate, downy cup. 



The tree and its foliage resemble laurtfolia, but the acorns and the 

 shallow cup of this species are quite different; the long falcate lobes of 

 many leaves point to falcata or Catesbcet as the other parent, while the 

 larger size of the acorn and the deep cup indicate the latter as the most 

 probable Notwithstanding these signs of hybridity, the probability is not 

 excluded that we may have nothing but an abnormal form of laurtfolia 

 befoi-e us. 



o^. imbricaria X nigra; ^. tridentata, Eng. in Hb. ; ^. nigra var. 

 tridenfaia, DC. I.e. 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 

 elliptical to obovate, entire or often coarsely 3-dentate at the apex, occa- 

 sionally with a few teeth on the sides ; 4-7 inches long, 2 or 3 wide ; 

 base rounded or acutish ; upper surface dark, shining green, lower one 

 pale, and in September not yet quite glabrate; petiole 4-10 lines long. 

 Acorns closely sessile ; the hemispherical, turbinate, canescent cup about 

 half-enclosing the globose nut. 



^. imbricaria Y^palustris was observed by me a few years ago, 8 miles 

 west of St. Louis, in a little dell where imbricaria abounds; paltistris, 

 coccinca, 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. Meehanof Germantown has furnished fine young plants, completely 

 agreeing in character with the parent. — Leaves slightly revolute in ver- 

 nation, though not as much as in imbricaria, pvibescent, especially be- 

 low, but completely denudated before the end of May. Full-grown leaves 

 broad-lanceolate, mostly acute at base, entire or more frequently with a 



