Zonneveld & Duncan (2003) divided Agapanthus into six species ( A. africanus, A. campanulatus, A. caulescens, A. coddii, A. inapertus, A. praecox ). Four additional taxa were recognised by Leighton (1965) as species ( A. comptonii, A. dyeri, A. nutans, A. walshii ), but were given subspecific rank by Zonneveld & Duncan. All species recognized by Leighton or by Zonneveld and Duncan are listed below. A. orientalis is also listed.
Agapanthus is a genus of herbaceous perennials that mostly bloom in summer. The leaves are basal and curved, linear, and up to 60 cm (24 in) long. They are arranged in two rows.
The inflorescence is a pseudo-umbel subtended by two large bracts at the apex of a long, erect scape, up to 2 m (6.6 ft) tall. They have funnel-shaped flowers, in hues of blue to purple, shading to white. Some hybrids and cultivars have colors not found in wild plants. The ovary is superior. The style is hollow. Agapanthus does not have the distinctive chemistry of Alliaceae.
Four valid botanical names have Agapanthus as their basionym.
In 1985, Dahlgren, Clifford, and Yeo placed Agapanthus in Alliaceae, close to Tulbaghia . Their version of Alliaceae differed from any that are recognized today in that it included Agapanthus and in that it included several genera that would later be transferred to Themidaceae.
In 1996, in a phylogenetic analysis of DNA sequences of the gene rbcL, Themidaceae was resurrected and
Agapanthus
was removed from Alliaceae. The authors found
Agapanthus
to be sister to Amaryllidaceae and transferred it to that family. This was not accepted by the Angiosperm Phylogeny Group when they published the APG system in 1998, because the clade consisting of
Agapanthus
and Amaryllidaceae had only 63% bootstrap support. The APG system recognized