''Aichryson'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of 16 species of succulent, subtropical plants, native to the

Canary Islands The Canary Islands (; ) or Canaries are an archipelago in the Atlantic Ocean and the southernmost Autonomous communities of Spain, Autonomous Community of Spain. They are located in the northwest of Africa, with the closest point to the cont ...

Azores The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...

, and

Madeira Madeira ( ; ), officially the Autonomous Region of Madeira (), is an autonomous Regions of Portugal, autonomous region of Portugal. It is an archipelago situated in the North Atlantic Ocean, in the region of Macaronesia, just under north of ...

. The species of ''Aichryson'' are not frost-resistant. They are related to ''

Sempervivum ''Sempervivum'' () is a genus of about 40 species of flowering plants in the family (biology), family Crassulaceae, commonly known as houseleeks. Other common names include liveforever (the source of the taxonomical designation ''Sempervivum'', l ...

, Jovibarba, Greenovia,

Aeonium ''Aeonium'', the tree houseleeks, is a genus of about 35 species of succulent, subtropical plants of the family Crassulaceae. Many species are popular in horticulture. The genus name comes from the ancient Greek αἰώνιος / aiōnios (ageles ...

'' and ''

Monanthes ''Monanthes'' is a genus of small, succulent, subtropical plants of the family Crassulaceae. Most species in the genus are endemic to the Canary Islands, with one species also endemic to the Savage Islands and another to the High Atlas mountains ...

'', readily seen in their similar flowers. The genus name comes from a contraction of the Greek "aei" (always) and "chrysos" (gold). Several species are cultivated as ornamental plants. The hybrid

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

''Aichryson'' × ''aizoides'' var. ''domesticum'' 'Variegatum' is a recipient of the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

Taxonomy

Recent phylogenetic studies of Crassulaceae indicate that ''Aichryson'' is closely related to ''

'' and ''

'' (both genera are also largely endemic to the Canary Islands). Two other genera of Crassulaceae that have many-parted (polymerous) flowers (''

'' and '' Jovibarba'') are not closely related to the three Canary Island genera.Mort et al. (2002). ''Systematic Botany'', 27: 271–288 On the Canary Islands, the center of species diversity seems to be the island of

La Palma La Palma (, ), also known as ''La isla bonita'' () and historically San Miguel de La Palma, is the most northwesterly island of the Canary Islands, a Spanish autonomous community and archipelago in Macaronesia in the North Atlantic Ocean. La Pa ...

. Relationships within ''Aichryson'' were investigated by Fairfield et al. (2004) 'Plant Systematics and Evolution'' 248: 71–83 They found that the five subspecies of ''A. pachycaulon'' were not each other's closest relatives (monophyletic) and additional species may need to be erected after additional study.

Species

16 species, and several naturally-occurring interspecies hybrids, are accepted. * '' Aichryson × aizoides'' * '' Aichryson × azuajei'' * '' Aichryson bitumosum'' * '' Aichryson bollei'' * '' Aichryson × bramwellii'' * '' Aichryson brevipetalum'' * '' Aichryson × buchii'' * '' Aichryson × cumbrense'' * '' Aichryson dichotomum'' * '' Aichryson divaricatum'' * '' Aichryson dumosum'' * ''

Aichryson laxum ''Aichryson'' is a genus of 16 species of succulent, subtropical plants, native to the Canary Islands, Azores, and Madeira. The species of ''Aichryson'' are not frost-resistant. They are related to ''Sempervivum, Jovibarba, Greenovia, Aeonium'' ...

'' * '' Aichryson pachycaulon'' (five subspecies have been recognized) * '' Aichryson palmense'' * '' Aichryson parlatorei'' * '' Aichryson porphyrogennetos'' * '' Aichryson × praegeri'' * '' Aichryson punctatum'' * '' Aichryson roseum'' * '' Aichryson santamariensis'' * '' Aichryson tortuosum'' – gouty houseleek * '' Aichryson villosum''

References

Crassulaceae genera Endemic flora of Macaronesia Succulent plants {{Crassulaceae-stub