Holly (Ilex spp.) species can be found in temperate and tropic zones throughout the world. You can recognize a holly by its simple, alternate leaves which are sometimes prickly on the edges. Hollies are typically dioecious, meaning that individuals produce either male or female flowers. Flowers are small and white with four petals. Hollies produce drupes in the winter which are variable in color and may be an important food resource for wildlife.
There are six species of holly on the Domain of Sewanee: The University of the South. Of these, one is nonnative. When we think of holly, we imagine an evergreen shrub with bright red berries (i.e. Ilex opaca – American holly). However, the majority of the hollies native to Sewanee are deciduous, meaning that they lose their leaves in the fall. Some of these deciduous hollies are nearly impossible to tell apart without examining their flowers or berries
Ilex ambigua (Sand holly) and Ilex montana (Mountain Winterberry) are deciduous hollies with rounded serrate leaves which can end in a point and red drupes. Difficult to distinguish from one another without fruits or flowers, I. montana is often classified as a variety of I. ambigua. Both can be found on the plateau surface. Telling these two species apart was an issue that we encountered last summer as our summer research assistants surveyed Franklin State Forest; we gave it our best shot, but will probably lump the two species together in our analyses.
Another plateau surface holly, Ilex verticillata (Winterberry) can have smaller leaves and has an affinity for moist habitats. I. verticillata is used as an ornamental and for flower arrangements due to its abundant bright red drupes. Ilex longipes (Georgia Holly) resembles the other hollies mentioned above, but it may be differentiated by its habitat – our collections have only confirmed it to be present on upper dry slopes of the cove.
Ilex crenata (Japanese holly) is nonnative with small glossy leaves and black drupes. This escaped ornamental can be found on the plateau surface around Sewanee.
Finally, Ilex opaca (American holly) is the instantly recognizable evergreen holly that can be found throughout the plateau surface, plateau wetlands, and floodplains in the cove. This tree produces thick, glossy leaves with sharp points. The leaves can provide shelter to native animals, and the red drupes are often eaten by birds. I. opaca has been cultivated and is a common symbol of the holiday season.
(Photographs of hollies courtesy of Chris Parrish)