Ilex opaca

Ilex opaca
Name	American holly
Genus	Ilex
Species	opaca
Authority	Aiton
Family	Aquifoliaceae

Ilex opaca is a native North American evergreen tree commonly called American holly. It is valued for ornamental use, cultural associations, and wildlife forage, appearing in literature, art, and horticultural catalogs across the United States and Canada. Populations are documented in botanical surveys, conservation assessments, and floras maintained by institutions such as the Smithsonian, Kew, and the United States Botanic Garden.

Description

Ilex opaca grows as a small to medium-sized tree frequently cited in field guides produced by the New York Botanical Garden, Missouri Botanical Garden, and Royal Botanic Gardens, Kew. Leaves are leathery and spiny, a characteristic described in monographs from Harvard University Herbaria and the Arnold Arboretum. Mature specimens develop reddish drupe fruits that feature in phenological records kept by the National Phenology Network and Audubon Society surveys. Bark, crown shape, and branching patterns appear in dendrological treatments from the Arnold Arboretum, Yale School of Forestry, and US Forest Service manuals.

Taxonomy and nomenclature

The taxonomic placement of Ilex opaca resides in the family Aquifoliaceae as treated in floras such as Flora of North America and treatments by the Royal Botanic Gardens, Kew. Authoritative nomenclatural entries are maintained by institutions like the International Plant Names Index, Missouri Botanical Garden’s Tropicos database, and the USDA PLANTS database. Historical descriptions appear in botanical works by William Aiton and illustrations in botanical plates housed at the Biodiversity Heritage Library, Harvard University Herbaria, and the Linnean Society collections. Synonymy and varietal concepts have been discussed in monographs published through the Botanical Society of America and university press floras.

Distribution and habitat

Ranges of Ilex opaca are mapped in atlases produced by the United States Geological Survey, NatureServe, and state natural heritage programs such as those in Virginia, North Carolina, and Florida. Populations occur across a swath of the eastern United States documented by the Biota of North America Program and by botanical surveys conducted by institutions like the University of Georgia Herbarium and the North Carolina Botanical Garden. Habitats include mixed hardwood forests referenced in Appalachian Plateau vegetation studies, coastal plain pine–oak communities described by the US Forest Service, and urban plantings recorded by municipal arboreta including the Dallas Arboretum and Atlanta Botanical Garden.

Ecology and wildlife interactions

Ilex opaca provides food and cover for wildlife noted in field guides and studies by the National Audubon Society, Cornell Lab of Ornithology, and the Wildlife Society Bulletin. Fruit consumption by birds such as species listed in guides by Roger Tory Peterson and the Birds of North America series, as well as mammals recorded in studies by the Smithsonian and the Mammal Society, supports seed dispersal examined in ecological journals like Ecology and Journal of Wildlife Management. Pollination and floral visitors are documented in entomological surveys from the Entomological Society of America and university extension publications from Penn State and University of Florida. Disease and pest interactions, including records from the American Phytopathological Society and USDA pest alerts, relate to fungal and insect agents treated in integrated pest management literature from Kansas State University and Cornell University.

Cultivation and uses

Cultivation practices for Ilex opaca are detailed in horticultural manuals from the Royal Horticultural Society, Missouri Botanical Garden Plant Finder, and the Brooklyn Botanic Garden. Uses include ornamental planting in public landscapes documented by the United States Botanic Garden, floral arrangements cataloged by the American Institute of Floral Designers, and traditional decorations referenced in Smithsonian Folkways collections and holiday guides from the Library of Congress. Wood uses and material properties are described in forestry publications from the US Forest Service and academic presses such as Oregon State University Extension. Propagation, grafting, and cultivar development are detailed in extension bulletins from Clemson University, North Carolina State University, and the University of Tennessee.

Conservation and threats

Conservation status assessments for Ilex opaca are maintained by NatureServe, state natural heritage programs, and the IUCN Red List assessments compiled by botanical institutions including Kew and the Royal Botanic Gardens. Threats cited in conservation literature include habitat loss discussed in reports by The Nature Conservancy, urbanization studies by the Lincoln Institute of Land Policy, and invasive species impacts detailed by the National Invasive Species Council. Management and restoration guidance appears in conservation plans by the US Fish and Wildlife Service, regional botanical gardens, and university conservation programs such as those at Duke University and University of California Cooperative Extension.

Category:Aquifoliaceae Category:Flora of the Eastern United States Category:Ornamental trees