Quercus nigra L., Fagaceae

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Common name: Water-oak.

Voucher: Kostadinov 109, (URV)

Brief description: Subgenus Erythrobalanus, red and black oaks.  A monoecious tree to 25 m with smooth young bark which gets scaly edges with age; the twigs are glabrous at maturity. Leaves are cuneate-obovate to cuneate-spatulate, broadened distally, simple, alternate, entire or shallowly and irregularly 2-5 lobed, pinnately veined, the margins entire. The foliage is dull green and glabrous except sometimes for some stellate 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 saucer-shaped. The acorns mature at the end of the second season and sprout at the beginning of the third.

Campus data: Frequent in the wild and in cultivation. More than thirty individuals encountered.