Mimosaceae, the mimosa family, has 40 genera and about 2000 species. Mimosaceae are recognizable by their binpinnately compound leaves with oval leaflets. Their compound flowers usually appear in colorful hemispherical or spherical tufts.

Recently the "legume family" Leguminosae was broken into three families: Mimosaceae, Caesalpinaceae, and Fabaceae (aka Papilionaceae).  You will frequently see Mimosaceae species represented under the Leguminosae or Fabaceae.

Superkingdom Eukaryota
Kingdom Plantae
Division Magnoliophyta (formerly Phylum Angiospermae)
Class Magnoliopsida (formerly Class Dicotyledonae)
Subclass Rosidae
(former Family Leguminosae)
Family Mimosaceae (Former subfamily Mimosoideae)


1Acacia is frequently classified in the Ingeae.

Sources:
Mimosaceae page of Dr. Gerald Carr, Professor of Botany, University of Hawaii
http://www.botany.hawaii.edu/faculty/carr/mimos.htm

L. Watson and M. J. Dallwitz (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 14th December 2000.
at http://biodiversity.uno.edu/delta/

University of Connecticut Ecology & Evolutionary Biology Conservatory
http://florawww.eeb.uconn.edu/

University of Western Australia Department of Botany
http://www.botany.uwa.edu.au/systematics/