Distribution. Dry gravelly slopes and ridges often in the shade of oaks and other large trees; Island of Cape Breton and the shores of the Bay of Chaleur, through the valley of the St. Lawrence River, and along the northern shores of Lake Huron to western Ontario, Manitoba, Minnesota, eastern North Dakota, the foothills of the Black Hills of South Dakota, eastern, northern and northwestern Nebraska, eastern Kansas and Oklahoma, and southward to northern Florida and eastern Texas; most abundant and of its largest size in southern Arkansas and in Texas. From Quebec and Ontario to western New England, western New York, Ohio and in Central Michigan, the glandular form prevails: the two forms occur in New Jersey, Pennsylvania, Indiana, northern Illinois, southwestern Missouri, Oklahoma, and southward on the high Appalachian Mountains. 2. Ostrya Knowltonii Cov. Ironwood. [Illustration: Fig. 193] Leaves elliptic to obovate, acute or round at apex, gradually narrowed and often unequal at the rounded cuneate rarely cordate base, sharply serrate with small triangular callous teeth, covered with loose pale tomentum when they unfold, at maturity dark yellow-green and pilose above, pale and soft-pubescent below, 1′—2′ long, 1′—1½′ wide, with a slender yellow midrib slightly raised on the upper side, and slender primary veins connected by obscure reticulate veinlets; turning dull yellow in the autumn before falling; petioles ⅛′—¼′ long; stipules pale yellow-green, often tinged with red toward the apex, ½′ long, about ½′ wide. Flowers: staminate aments on stout stalks covered with rufous tomentum and sometimes ½′ long, rarely sessile, about ½′ long during their first season, with dark brown puberulous scales gradually contracted into a long slender subulate point, becoming when the flowers open 1′—1¼′ long, with broadly ovate concave scales abruptly narrowed into a nearly triangular point, yellow-green near the base, bright red above the middle; pistillate aments about ¼′ long, with ovate-lanceolate light yellow-green puberulous scales ciliate on the margins. Fruit: nuts ¼′ long, gradually narrowed at the apex, their involucres 1′ long, nearly glabrous at the apex, sometimes slightly stained with red toward the base, in clusters 1′—1½′ long and about ¾′ broad, on stems ½′ in length.