Understory shrubs include flowering dogwood ("Cornus florida") and American holly ("Ilex opaca"). Flowering dogwood ("Cornus florida") is a common understory tree. Flowering dogwood ("Cornus florida") blooms in early spring. The similar Kousa dogwood ("Cornus kousa"), native to Asia, flowers about a month later. It is a member of the dogwood genus "Cornus" and the family Cornaceae. "Cornus" in Latin means horn, this is describing the dogwoods hard wood. Newby Hall also holds the National Collection of the genus "Cornus" (dogwoods). In northern temperate areas, Cornaceae are well known from the dogwoods "Cornus". "Cornus canadensis" is a mesophytic species that needs cool, moist soils. The mixed-wood forest floor is blanketed with moss, wood fern ("Dryopteris"), and bunchberry ("Cornus canadensis"). The drupes of species in the subgenera "Cornus" are edible. A chemical substance isolated from "Cornus officinalis" also may enhance the motility of human sperm. It has sometimes been considered a synonym of the Asian species "Cornus alba". Cornus controversa (wedding cake tree), syn. Cornus kousa, is a small deciduous tree tall, in the family Cornaceae.