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Voucher: Kostadinov 165, (URV)
Brief description: Subgenus Erythrobalanus, red and black oaks. A monoecious tree to 25 m with glabrous, reddish twigs. Leaves are narrowly oblong to lanceolate or elliptic to obovate, simple, alternate, entire, pinnately veined, the margins entire. The foliage is glabrous except for some hairs in the vein axils beneath. Flowers are unisexual, the staminate in slender catkins, the pistillate solitary or in small spikes. Fruits are a nut (acorn), partly enclosed by the persistent involucre -- the acorn cup. The acorn cup is depressed-hemispheric. The acorns mature at the end of the second season and sprout at the beginning of the third.
Campus data: Very rare in the wild on campus. Two individuals encountered.