Ilex opaca, the American holly, is a species of holly, native to the eastern and south-central United States, from coastal Massachusetts south to central Florida, and west to southeastern Missouri and eastern Texas.

Callophrys henrici, the Henry's elfin or woodland elfin, is a North American butterfly in the family Lycaenidae. In Canada it is found from southern Manitoba to southern Nova Scotia. It has two main groups of populations in the United States; the first is found along the Atlantic Coast and uses various hollies (Ilex) as host plants; and the second is found mainly in the north and the Appalachians where they use redbud as a host plant. Henry's elfin is increasing in New England because of an introduced buckthorn it now uses as a host plant. It is listed as a species of special concern in the US state of Connecticut.