''Samolus'' (known as brookweed, or water pimpernel) is a widely distributed genus of about a dozen species of water-loving herbs. According to the APG III classification, this genus belongs to the family

Primulaceae The Primulaceae , commonly known as the primrose family (but not related to the Onagraceae, evening primrose family), are a family (biology), family of Herbaceous plant, herbaceous and woody flowering plants including some favourite garden plants ...

in the order Ericales. It was considered as closely related to a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

comprising the

Theophrastaceae Theophrastoideae is a small subfamily of flowering plants in the family Primulaceae. It was formerly recognized as a separate family Theophrastaceae. As previously circumscribed, the family consisted of eight genera and 95 species of trees or shr ...

, and was treated as part of that family or in its own monogeneric family, the Samolaceae. The APG III system does not recognize these families and instead includes all genera formerly belonging to Theophrastaceae in the family Primulaceae.

Species

The last complete taxonomic treatment of this genus recognizes the following species: Although some local floras recognize the North-American populations of ''S. valerandi'' as a separate species (''S. parviflorus'') or subspecies (''S. valerandi'' ssp. ''parviflorus''), molecular and morphological data indicate that ''S. vagans'' and ''S. parviflorus'' should not be regarded as separate species but as part of a widespread "''S. valerandi'' species complex.

References

Bibliography

* Primulaceae genera {{Primulaceae-stub