Atriplex are C-plants, with a characteristic leaf anatomy (kranz anatomy). The genus "Atriplex" is distributed nearly worldwide from subtropical to temperate and to subarctic regions. Most species-rich are Australia, North America, South America and Eurasia. Many species are halophytes and are adapted to dry environments with salty soils. The genus evolved in Middle Miocene, the C-photosynthesis pathway developed about 14.1-10.9 million years ago, when the climate became increasingly dry. The genus diversified rapidly and spread over the continents. The C"Atriplex" colonized North America probably from Eurasia during the Middle/Late Miocene, about 9.8-8.8 million years ago, and later spread to South America.
Insectivorous Plants (book) of the book enumerates his experiments on "Drosera rotundifolia". Darwin then turns his attention to other varieties of insectivorous plants and makes comparisons, noting that in some cases different parts of the leaf are used for digestion and others for absorption of decayed matter (p. 330–331). He conjectured that plants may become adapted exclusively to one of these functions by gradually losing the other over a period of time. This would explain how "Pinguicula" and "Utricularia" came to use different functions even though they belong to the same family; p. 331). Darwin wrote in his autobiography that "the fact that