The Soap Plants, Soaproots or Amoles are the genus Chlorogalum of flowering plants. Less common names for them include Soap Lilies. They are endemic to western North America, from Oregon to Baja California, and are mostly found in California.
The Soap Plants grow as perennial plants, from a bulb, more or less elongated depending on the species. The bulbs can be white or brown, and in most species are very fibrous. The leaves grow from the base of the plant. The flowers are born on a long central stem, and appear to have six rather separate petals (not all are petals in the technical sense). There are 6 stamens, which are rather prominent in most species.
The placement of the genus Chlorogalum is currently uncertain. Until the 1980s, it was generally treated in the Lily family, Liliaceae, in the order Liliales, and conservative taxonomic sources such as ITIS still put it there. The consensus of more recent classifications has been that this is untenable, and for a time Chlorogalum was placed in the hyacinth family Hyacinthaceae, in the order Asparagales. According to Pfosser and Speta (1999), however, molecular systematics now shows that this placement too is wrong at the family level, though they confirm that the genus should be within the Asperagales. Pfosser and Speta conclude that, along with genus Camassia, Chlorogalum seems to be most closely related to the families Agavaceae, Funkiaceae and Anthericaceae. The emerging consensus seems to be that these two genera should be placed in an expanded Agavaceae.
Five species are currently classified in the genus. All except the Wavy-leafed Soap Plant, Chlorogalum pomeridianum, have rather restricted distributions, with little overlap. The Wavy-leafed Soap Plant, however, has a range that virtually encompasses those of all other members of the genus, and is the most common of them.