Carya glabra is a highly polymorphic species. Tight-barked trees bearing large pear-shaped fruits are common along the Gulf Coast ( C . glabra var. megacarpa and C . leiodermis , C . magnifloridana ). Trees with exfoliating bark, reddish petioles, and small, compressed, ellipsoid fruits that dehisce to the base (i.e., C . ovalis ) are more common at higher latitudes. Carya glabra intergrades with C . floridana , C . pallida , and C . texana , and it is reported to hybridize with the diploid C . cordiformis ( C . × demareei Palmer). The extreme northern ovalis form of the species also appears to hybridize with the typical glabra in areas of sympatry.