The former Agapanthaceae, now Agapanthoideae subfamily is an entirely South African family with Agapanthus as the sole genus. Plants are deciduous or evergreen and contain saponins which are responsible for the characteristic slimy sap. Each blue or occasionally white flower has 6 tepals joined into a short tube at the base, 6 stamens, and a superior 3-chambered ovary with many winged seeds. Plants grow from rhizomes often forming large colonies. Leaves are strap-shaped 2 ranked and the flower stalks are leafless bearing an umbel of showy flowers. According to Alan Meerow this family has been tossed between the two families Alliaceae and Amaryllidaceae. It has a superior ovary, which is characteristic for the Alliaceae, and lacks particular (amaryllid) alkaloids common to the Amaryllidaceae and also lacks the allyl sulfides found in the Alliaceae. In Dahlgren's work Agapanthus was allied (albeit not closely) with Tulbaghia, another South African genus, based on anatomical similarities (rhizomatous, flat leaves, umbel-like inflorescences, tepals fused basally, etc.) Molecular evidence indicates a closer relationship to the Amaryllidaceae. In 2003 the Angiospermy Phylogeny Group (AGP II report) suggested lumping this family "back" into the Alliaceae family.
In the most current APGIII and AGPIV systems, the Amaryllidaceae includes Alliaceae and Agapanthaceae as subfamilies.