Delonix regia is a species of flowering plant in the bean family Fabaceae, subfamily Caesalpinioideae native to Madagascar. It is noted for its fern-like leaves and flamboyant display of orange-red flowers over summer. In many tropical parts of the world it is grown as an ornamental tree and in English it is given the name royal poinciana, flamboyant, phoenix flower, flame of the forest, or flame tree.

Caesalpinioideae is a botanical name at the rank of subfamily, placed in the large family Fabaceae or Leguminosae. Its name is formed from the generic name Caesalpinia. It is known also as the peacock flower subfamily. The Caesalpinioideae are mainly trees distributed in the moist tropics, but include such temperate species as the honeylocust and Kentucky coffeetree. It has the following clade-based definition:The most inclusive crown clade containing Arcoa gonavensis Urb. and Mimosa pudica L., but not Bobgunnia fistuloides (Harms) J. H. Kirkbr. & Wiersema, Duparquetia orchidacea Baill., or Poeppigia procera C.Presl