Tetrataxis,a monotypic endemic of Mauritius, has been known since the 1790s only by the type collection in the Paris Herbarium. Now a colony of seven individuals has been discovered in a valley south‐east of the type area. The small trees grow in saturated soil in a low open wet forest. Vegetatively, they resemble the more commonSyzygium or Eugenia.Characteristics of the pollen and seed, anatomy of stems and leaves, and an approximate chromosome number are reported for the first time. A lectotype is selected from material of the original collection.Tetrataxisdisplays a number of advanced characters. It appears to have no close affinity to any single member of the famil