268 TREES OF NORTH AMERICA 



Quercus Leana, Nutt., scattered usually in solitary individuals from the District of 

 Columbia and western North Carolina to southern Michigan, central and northern Illinois 

 and southeastern Missouri, is believed to be a hybrid between this species and Quercus 

 velutina. 



X Quercus tridentata Engelm., described as a hybrid of Quercus imbricaria and Q. mari- 

 landica first found at Allenton, Saint Louis County, Missouri, occurs also near Olney, 

 Richland County, Illinois. 



X Quercus exacta Trel., believed to be a hybrid of Quercus imbricaria and Q. palustris, 

 occurs near Olney, Richland County, Illinois, and at Crown Point, Lake County, Indiana. 



21. Quercus hypoleuca Engelm. 



Leaves lanceolate or oblong-lanceolate to elliptic, occasionally somewhat falcate, acute 

 and often apiculate at apex, cuneate or bounded or cordate at the narrow base, entire 

 or repandly serrate above the middle with occasionally small minute rigid spinose teeth, 



Fig. 245 



or on vigorous shoots serrate-lobed with oblique acute lobes, when they unfold light red, 

 covered with close pale pubescence above and coated below with thick hoary tomentum, 

 at maturity thick and firm, dark yellow-green and lustrous on the upper surface, covered 

 on the lower with thick silvery white or fulvous tomentum, 2'-4' long, |'-1' wide, with 

 thickened revolute margins; turning yellow or brown and falling gradually during the 

 spring after the appearance of the new leaves^ petioles stout, flattened, pubescent or to- 

 mentose, f'-J' in length. Flowers: staminate in slender aments 4 '-5' long; calyx slightly 

 tinged with red, covered with pale hairs and divided into 4 or 5 broadly ovate rounded lobes; 

 anthers acute, apiculate, bright red becoming yellow; pistillate mostly solitary, sessile OP 

 short-stalked, their involucral scales thin, scarious, and soft-pubescent; stigmas dark red. 

 Fruit sessile or borne on a stout peduncle up to \' in length, usually solitary; nut ovoid, 

 acute or rounded at the narrow hoary-pubescent apex, dark green and often striate when 

 ripe, becoming light chestnut-brown in drying, '-' long, the shell lined with white to- 

 mentum, inclosed for about one third its length in a turbinate thick cup pubescent on 

 the inner surface, and covered by thin broadly ovate light chestnut-brown scales rounded 

 at apex and clothed, especially toward the base of the cup, with soft silvery pubescence. 



A tree, usually 20-30 or sometimes 60 high, with a tall trunk 10'-15' in diameter, 

 slender branches spreading into a narrow round-topped inversely conic head, and stout 

 rigid branchlets coated at first with thick hoary tomentum disappearing during the first 

 winter, becoming light red-brown often covered with a glaucous bloom and ultimately 

 nearly black; frequently a shrub. Winter-buds ovoid, obtuse, about ' long, with thin 



