Samolus is a widely distributed genus of about a dozen species of water-loving herbs. It is considered sister to a clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 comprising the Theophrastaceae

Theophrastaceae

Theophrastaceae is a small family of flowering plants. As currently circumscribed, the family consists of seven genera and 95 species of trees or shrubs, native to tropical regions of the Americas....

, so it may be treated as part of that family or in its own monogeneric family, the Samolaceae. Although the latter option is not uncommon, at present the Angiosperm Phylogeny Website

Angiosperm Phylogeny Website

Angiosperm Phylogeny Website is a well-known web site dedicated to research on Angiosperm phylogeny and taxonomy.The site is hosted by the Missouri Botanical Garden website and maintained by researcher Peter F. Stevens, who is a member of the Angiosperm Phylogeny Group...

 recommends the former.

Species

The last complete taxonomic treatment of this genus recognizes the following species:

• Samolus cinerascens
• Samolus dichondrifolius
• Samolus ebracteatus
• Samolus junceus
• Samolus porosus
• Samolus pyrolifolius
• Samolus repens
  Samolus repens
  Samolus repens is a species of water pimpernel native to Australia, New Zealand and adjacent Pacific islands, and South America , where it is common in temperate and subtropic coastlines. This species has small white or occasionally pink flowers with a flowering period from September through to...
  
  
• Samolus junceus
• Samolus spathulatus
• Samolus subnudicaulis
• Samolus vagans
• Samolus valerandi
  Samolus valerandi
  Samolus valerandi is a species of water pimpernel native to a very wide area across Europe, Africa, Asia, Australia, and the Americas. Common names include Thin-Leaf Brookweed, Water Cabbage, and Water Rose.-Cultivation:...
  
  

Samolus valerandi is native to a very wide area across Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, Africa

Africa

Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

, Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, and the Americas

Americas

The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

; the other species have more restricted ranges.