Poisonwood

Metopium toxiferum
Family: Anacardiaceae

Natural History

Poisonwood, also known as Florida poisontree or hog gum, is related to poison sumac and poison oak, all members of the cashew or sumac (Anacardiaceae) family. This beautiful tree grows abundantly in the Keys and can also be found in various ecosystems in southern Florida. Its range in tropical America extends from Florida to the Bahamas, Honduras, and the West Indies.

The sap contains alkaloids that cause serious skin and mucus irritations after skin contact. Any part of the tree may carry the sap so handling any part of the poisonwood should be avoided. If you live or work in south Florida the ability to recognize and identify poisonwood is beneficial. You can find poisonwood inhabiting hammocks, pinelands, and sandy dunes near salt water.

The wood is dark brown streaked with red and is heavy and hard, but is not strong. The wood has no commercial value. The gummy sap of the bark has been used medicinally but with extreme caution. The fruit of the poisonwood is a favorite food source for the rare white-crowned pigeon. Other birds and animals also enjoy the fruit.


 

Identifying Characteristics

Size/Form: Poisonwood is an evergreen shrub or medium tree that reaches heights of 25' to 35' or taller. It characteristically has a short trunk with stout arching limbs and drooping branches that form a spreading, rounded crown. Poisonwood is often a shrub in the pinelands and a larger tree in the hammocks.
Leaves: The leaves are odd-pinnately compound, alternately arranged, 6" to 10" long, and have 3 to 7, usually 5 leaflets. Each leaflet is 3" to 4" long by 2" to 3" wide and broadest near the base or middle. The oval to elliptical leaflets have smooth, glossy, dark green upper surfaces and are paler underneath. The leaf stem is smooth or finely hairy and swollen at the base. The leaflet base is wedged, rounded, or heart-shaped and the tip is acute or rounded. In addition to its leathery appearance, the leaflet has a margin that is thickened, slightly curled, and entire. Many leaflets will be blotched with irregular spots of black resin.
Fruit: The fruit is a yellow-orange drupe that is about ½" long. The fruit hangs loosely in clusters and each drupe contains one, ¼", hard, brown seed.
Bark: The reddish-brown or gray bark is thin and has dark, oily patches from the gummy sap. Older trunks have scaly bark.
Habitat: Poisonwood grows near salt water on shorelines and in sandy dunes, tropical and coastal hammocks, and rockland pinelands.

 

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Bark

Leaf

Fruit

 

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