Sapindaceae, the Soapberry Family
This is a fast-growing, evergreen, usually single-trunked tree that can reach 35 feet in height. The smooth outer bark is gray in color, but the inner bark is often orange, hence the common name carrotwood. The leaves are alternately arranged and pinnately compound, with four to 10 leaflets on short, swollen stalks. The glossy, leathery leaflets may be oblong, elliptic or obovate in shape and have a rounded apex that is often retuse (notched). In Florida, plants usually flower between January and March, with fruits maturing about three months later. The small (less than ½ inch wide) greenish-white to yellow flowers are borne in branched, often pendulous, axillary inflorescences. The flowers are unisexual, with both male and female flowers occurring on a single inflorescence. The fruits are three-lobed to three-ridged, woody capsules that are orangish-yellow when ripe and measure ½ to 1 inch in diameter. At maturity, the fruit split open to reveal three shiny, black seeds that are enclosed in a fleshy orange to red tissue called an aril.
Carrotwood is native to New Guinea and the northern and eastern coasts of Australia. It is cultivated as an ornamental in subtropical and tropical regions and has become increasingly popular as a landscape tree in Florida, Hawaii and California.
This species has escaped from cultivation and may be found in both disturbed and undisturbed coastal habitats on the central and southern peninsula. Naturalized plants have been documented from several counties, ranging from Volusia County to Miami-Dade County on the east coast, and as far north as Pasco County on the west coast. Tolerant of poor soils, periodic inundation, drought, salt and shade, carrotwood has been found in a variety of habitats including coastal hammocks, dunes, strands, mangrove swamps, marshes, pine scrub, flatwoods and spoil islands.
Carrotwood might be confused with the rare and endangered native species American toadwood (Cupania glabra), which is found in the Florida Keys, the West Indies, and tropical America. American toadwood can be distinguished from carrotwood by its leaflets with scalloped or coarsely toothed margins, green-colored fruits and green-colored arils enclosing the seeds. Tulipwood (Harpullia arborea), a tree from the Asian and Australian tropics that is cultivated and sometimes naturalized in South Florida, is also superficially similar to carrotwood. However, the fruits of tulipwood have only two valves and the seeds are not enclosed in an aril (in contrast to carrotwood, which has three-valved fruit with arillate seeds).
Carrotwood trees produce seeds in abundance, and the fleshy, brightly colored arils that surround the seeds are especially attractive to birds, the principal agents of dispersal. Multiple species of bird have been observed consuming carrotwood seeds. The fish crow (Corvus ossifragus), in particular, has been implicated in spreading carrotwood to offshore islands and other remote coastal habitats. Seedlings are often observed sprouting below birds' roosts.
Carrotwood was introduced to Florida as an ornamental as early as 1955 but became popular as a landscape tree in southern Florida in the 1970s and 1980s. By 1990, it was observed in a variety of natural communities, especially moist coastal lowlands such as mangroves, and it was subsequently listed as a Category I invasive by the Florida Exotic Pest Plant Council (FLEPPC). Once established, fast-growing carrotwood can form dense monocultures that eventually outcompete and displace native vegetation. It was added to the Florida noxious weed list in 1999.
Lockhart, C.S., D.F. Austin, W.E. Jones and L.A. Downey. 1999. Invasion of Carrotwood (Cupaniopsis anacardioides) in Florida Natural Areas (USA). Natural Areas Journal 19: 254-262.