Species Factsheets

Ilex opaca

American Holly

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State Status: Pennsylvania Threatened (PT)
PBS Status: Pennsylvania Threatened (PT)
Federal Status:

Global Rank: G5 rank interpretation
State Rank: S2

Did You Know?

The leaves of this species have been used to make tea to alleviate measles, colds, the flu and pneumonia.

Ilex opaca

Description

American holly (Ilex opaca) is an evergreen shrub or small tree that grows to 15m in height. It can be easily recognized in any season by its alternately arranged, thickish, evergreen leaves that have a sharp spine at the tip and additional spines along the margin. The flowers, appearing in May and June, are unisexual, so that the familiar berry-like fruit, red at maturity, can be found only on female plants.

Rank Justification

Imperiled in the nation or state because of rarity due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors making it very vulnerable to extirpation from the nation or state.

PABS

The PA Biological Survey (PABS) considers American holly to be a species of special concern, based on the relatively few native occurrences that have been recently confirmed. The species has a PA legal rarity status and a PABS suggested rarity status of Threatened.

Habitat

The species grows on wooded slopes and streambanks. It has also been grown as an ornamental, particularly in the southeastern counties, and may escape locally to woodlots, thickets, and fencerows.

Survey Dates

Flowers May - early June, fruits October - winter; evergreen leaves

Distribution

In Pennsylvania, it is near the northern end of its range, and occurs mostly in the southeastern counties.

American

Management

The conservation of American holly in Pennsylvania has concentrated on protecting populations that are believed to be indigenous and that represent native genotypes. Occurrences of the species that have resulted from escapes from plantings are of uncertain genetic origin and are considered to be of much lower conservation significance. As a woodland species, proper forest management and control of invasive species are important for the long term viability of American holly. Gathering of the branches of wild trees for winter decoration should be discouraged.

Conservation Status Map

American

Map Legend

NatureServe. 2017. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org.

http://www.bio.brandeis.edu/fieldbio/medicinal_plants/pages/Holly.html

  • NatureServe. 2018. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available at http://www.natureserve.org/explorer
  • Pennsylvania Natural Heritage Program. 2018.
  • Rhoads, A.F. and W.M. Klein, Jr. 1993. The Vascular Flora of Pennsylvania. American Philosophical Society, Philadelphia, Pennsylvania. Rhoads, A.F. and T.A. Block.
  • 2007. The Plants of Pennsylvania: An Illustrated Manual. 2nd edition. University of Pennsylvania Press, Philadelphia, Pennsylvania.
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