Acalypha integrifolia is a shrub measuring 2 meters, it has simple alternate leaves which are pale yellow green and can be red on the underside. The leaf margins are serrated, and leaf veins are reddish. The plant has reddish leaf stalks and stems. Male and female flowers are separate. The inflorescence comes out at the axillary, on a solitary spike measuring up to 20 centimeters long with small red flowers. The species produces a three-lobed, spiny, capsule fruit which contain pale brown ovoid seeds.
The species is endemic to the Mascarenes and occurs in the intermediate and upland forest. It is commonly found in the undergrowth and can colonise any area rapidly. The tiny seeds are dispersed by birds that facilitate the germination of the species.
The species is listed as ‘Least Concern’ in the IUCN Red Data List. Even though it is common in the forests, we can observe the decline of the population in other areas due to invasive exotic species and the disturbance of the soil by feral pigs. The plants have been used in forest restoration projects and as decorative plants in landscape projects.
In Réunion and Mauritius the leaves are used to make a decoction which is ingested as an astringent and purgative, used to eliminate intestinal worms. It is also used to treat skin infections.
The long spike of the inflorescence looks like the tail of the rat, hence its common name.