Digitaria insularis (sourgrass).

D. insularis is an aggressive perennial grass causing major weed problems in its native area, especially in Brazil, Paraquay and Bolivia. It was classed as a principal weed in Venezuela by Holm et al. (1979). It is a major weed where introduced to pastures in Hawaii, USA (Kuswata Kartawinata and Mueller-Dombois, 1972); also in Papua New Guinea (Chadhokar, 1978). In Hawaii, a weed risk assessment based on the Australia/New Zealand model rated the species at 20, i.e. high risk (PIER, 2012).

Euphorbia tithymaloides (devil's backbone).

Euphorbia tithymaloides is a succulent, perennial shrub widely cultivated as an ornamental plant. Native to the Americas, this species has been introduced in Africa, Asia and Oceania, occurring on rocky soils in dry, sunny habitats such as hillsides, wastelands and roadsides. Currently it is listed as invasive in New Caledonia, Wake Island, the British Indian Ocean Territory and Cuba. Despite being classified as high risk in the Hawaii-Pacific Weed Risk Assessment, its environmental impact on native species and habitats is unknown.

Noronhia emarginata (Madagascar olive).

Noronhia emarginata is a slow-growing evergreen tree native to Madagascar. The species has been introduced to several tropical and subtropical countries as an ornamental. It is widely but sporadically cultivated in tropical regions, primarily as an ornamental tree, and sometimes grown in various tropical botanical gardens. A very tough tree with a high tolerance for salt and wind, N. emarginata is well suited to coastal and seaside locations. The species has been recorded as invasive in Hawaii, but further evaluation was required based on the weed risk assessment. It is considered a highly invasive species in Bermuda, but no details on its impact are available. The species is not considered to be a weed which causes disturbance in gardens, nor does it impact any agricultural, forestry or horticultural activities. The species has not been documented in any undisturbed natural areas in Florida.