Iris subg. Iris
Subgenus Iris is one subgenus of "Iris". "Iris" as a plant was originally named by Carl Linnaeus in his book Systema Naturae (in 1735), with a great number of species being added into the genus. Including new ones that were found after the books publication. The division of irises into varies subgroups, has taken various forms over the years. By the 19th century botanists had created new genera such as "Evansia", "Hermodactylus", "Moraea", "Oncocyclus", and "Xiphion". Opinion was often divided whether to split the genus into several parts or lump them back into Iris. From J. G.  Baker, who separated some such as "Moraea" and "Xiphion" from Iris in his book 'Handbook of the Irideae' (published in London) in 1892. Then William R. Dykes, who clarified the situation by a compromise in his monograph "The Genus Iris" (by Cambridge University Press, 1913; later reprinted in 1974 by Dover). He was the first to term the subgroup as "Iris sect. Iris". G. Rodionenko's 1961 reclassification in "The Genus Iris" (written in Russian, Moscow, 1961) was more comprehensive in that he split the genus into five genera: Iris (which included all rhizomatous irises). A taxonomic revision by Brian  Mathew in 1981 ("The iris", New York: Universe Books), recognized six subgenera: "Nepalensis" Dykes, "Xiphium" (Miller) Spach, "Scorpiris" Spach, "Hermodactyloides" Spach, "Iris" L. and "Limniris" Tausch. Recently, DNA analysis has been used to determine groupings. The Iris subgenus has been divided into six sections; bearded irises (or pogon irises), Psammiris, Oncocyclus, Regelia, Hexapogon and Pseudoregelia. Sections "Oncocyclus" and "Regelia" are also called aril irises. Section bearded irises (or pogon irises). This is the largest section of the subgenus, the true bearded irises. Most irises come from Southern or eastern Europe. 'Pogon' refers to the Greek word for beard. It has  several species of iris including; It also includes thousands of ornamental plant cultivars, which have been divided into various height categories. Section::::"Psammiris". This section of irises was first described by Spach. Most of the Irises come from Russia and Northwest china. Mostly rhizomatous, and flowering in late spring. 'Psammiris' is derived from the Greek word for sand. It includes; Section::::"Oncocyclus". Oncocyclus irises are rhizomatous perennials. They also generally need rich soils that drain easy and are in full sun. Most also prefer a dry period after flowering. The Oncocyclus irises are mostly from Turkey, Caucasus and Iran. The flowers usually  only have one flower, which is veined or spotted. Some of these species have been bred with bearded irises to create unique colours and markings. Oncocyclus is a Greek word, with "onco" meaning mass, or bulk, and "cyclus" meaning circle. In 1846, the term 'Oncocyclus' was first used by C.H. Siemssen as the "Genus Oncocyclus" in 1846 in Botanische Zeitung. Baker then re-classified it to a subgenus in 1877, than Dykes lowered it to a section in 1914, where it currently remains. Section::::"Regelia". Mostly from the mountainous regions of Iran, Afghanistan and the Altai Mountains. Most irises have a  stem that has 2 flowers. It was named in 1904 by Robert Lynch in his book "The Book of The Iris" after Dr Regel. Hybrids of Regelia irises and Oncocyclus irises are known as 'Regelicyclous'. Section::::"Hexapogon". Mostly from the desert area of Central Asia, Iran and Afghanistan. Most irises have beards on the falls and standards. Note 'hexa' refers to the number 6 and 'pogon' refers to the Greek word for beard. Section::::"Pseudoregelia". Mostly from the mountainous regions of Eastern Asia. Most irises have flowers that have blotches or colour spots on.