Acalypha rubrinervis

Acalypha rubrinervis (string tree or stringwood) is an extinct plant in the spurge family (Euphorbiaceae), from the island of Saint Helena in the South Atlantic Ocean. It was called string tree on account of the thin pendulous inflorescences which resembled red strings. Disturbance following human settlement on the island destroyed its habitat and it was last seen in the 19th century. It is thus one of a number of island plants to have been driven to extinction by human activity (see List of extinct plants).

The genus to which it belongs, Acalypha, is a large one and includes island endemics as well as weeds and ornamentals. A. rubrinervis was a shrub or thicket growing on the central ridge of St Helena above 600 m elevation.