Cotyledon

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Eudicots
Cladus: Core eudicots
Ordo: Saxifragales

Familia: Crassulaceae
Subfamilia: Kalanchoideae
Genus: Cotyledon
Species: C. adscendens – C. barbeyi – C. campanulata – C. cuneata – C. egglii – C. eliseae – C. gloeophylla – C. orbiculata – C. papillaris – C. pendens – C. petiolaris – C. tomentosa – C. velutina – C. woodii – C. xanthantha

Source(s) of checklist:

Hassler, M. 2019. Cotyledon. World Plants: Synonymic Checklists of the Vascular Plants of the World In: Roskovh, Y., Abucay, L., Orrell, T., Nicolson, D., Bailly, N., Kirk, P., Bourgoin, T., DeWalt, R.E., Decock, W., De Wever, A., Nieukerken, E. van, Zarucchi, J. & Penev, L., eds. 2019. Species 2000 & ITIS Catalogue of Life. Published online. Accessed: 2019 November 26. Reference page.

Name

Cotyledon L. (1753), nom. cons.

Type species: C. orbiculata L. typ. cons.

Synonyms

Homotypic
Cotylaria Raf., Princ. Fond. Somiol. 25. 1814.
Umbilicaria Pers., Syn. Pl. 1: 510. 1805, nom. illeg. non Heist. ex Fabr. (1759).

Notes

Homonym
Cotyledon Brun ,1891 = Gutwinskiella G.De Toni (?, fossil)

References

Linnaeus, C. 1753. Species plantarum, exhibentes plantas rite cognitas, ad genera relatas, cum differentiis specificis, nominibus trivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas. Tomus I. Pp. [I–XII], 1–560. Impensis Laurentii Salvii, Holmiae [Stockholm]. BHL Reference page. : 429

Links

Hassler, M. 2019. Cotyledon. World Plants: Synonymic Checklists of the Vascular Plants of the World In: Roskovh, Y., Abucay, L., Orrell, T., Nicolson, D., Bailly, N., Kirk, P., Bourgoin, T., DeWalt, R.E., Decock, W., De Wever, A., Nieukerken, E. van, Zarucchi, J. & Penev, L., eds. 2019. Species 2000 & ITIS Catalogue of Life. Published online. Accessed: 2019 November 26. Reference page.
Govaerts, R. et al. 2019. Cotyledon in Kew Science Plants of the World online. The Board of Trustees of the Royal Botanic Gardens, Kew. Published online. Accessed: 2019 November 26. Reference page.
International Plant Names Index. 2019. Cotyledon. Published online. Accessed: November 26 2019.
Tropicos.org 2019. Cotyledon. Missouri Botanical Garden. Published online. Accessed: 26 November 2019.

Vernacular names
suomi: Mehilehdet
magyar: Köldökfű
svenska: Ökenklocksläktet

Cotyledon is one of some 35 genera of succulent plants in the family Crassulaceae. Mostly from Southern Africa, they also occur throughout the drier parts of Africa as far north as the Arabian Peninsula. Ten of its species are mostly confined to South Africa, where unlike Tylecodon, they occur commonly in both the winter and summer rainfall regions.[1] They may be found on coastal flats and rocky hillsides, or as cremnophytes on cliff faces. Their decussate, evergreen leaves are very variable in shape, even within some species, but the flowers are, apart from colour, very similar.[1]

Description
Cotyledon leaves (Cotyledon orbiculata)
Cotyledon flower (Cotyledon orbiculata)

Members of the genus are shrublets, generally succulent, with fleshily woody, brittle stems and persistent succulent leaves.[2][3]

The leaves are opposite. Leaf pairs generally are oriented at 90 degrees to their preceding and following pairs, as is common in the family Crassulaceae, but the leaf habit differs from say Tylecodon (in which the leaves are borne in spirals and are deciduous).

The flowers are pendulous and tubular, borne at the tips of stout, rather long peduncles, mainly in short cymes. Calyx 5-partite, corolla 5-lobed. Petals united in a tube or urn that generally is longer than broad, their triangular tips more or less pointed and recurved, 10 stamens arising from corolla near base and projecting or nearly projecting from the corolla. Gynoecium comprises 5 carpels, nearly or quite free, each carpel tapering into a slender style with an obliquely capitate stigma. Each carpel contains many small (typically less than 1 milligramme when ripe) globular, brown seeds.
Taxonomy

Together with Tylecodon, Kalanchoe and Adromischus it forms a sister clade to the family's basal Crassula clade.[1] Until the 1960s some 150 species were included in the genus Cotyledon,[4] but subsequently it was split into at least Adromischus, Dudleya, Rosularia, and Tylecodon, leaving probably less than two dozen species in Cotyledon.[5] Of these, about four are characteristically fynbos plants.[6]
Cultivation and uses

Most plants in the genus, and those that used to be included in the genus Cotyledon, are poisonous, even dangerously so. Some have been implicated in stock losses among goats, pigs and poultry. However, many species have long been used in traditional medicine. They have been applied for many purposes, ranging from magic charms to removal of corns.[7]

Cotyledon spp. are grown as garden and indoor subjects, practically independent of irrigation in all but full desert conditions, though they cannot survive poor light or bad drainage. Pests that affect them include sucking bugs, members of the suborder Auchenorrhyncha such as the mealy bug (Pseudococcus), and similar insects. The inflorescences of the larger species are sometimes used as components of dried arrangements in floral design.
Species list

Species include (among others):

Cotyledon adscendens[5]
Cotyledon barbeyi[5]
Cotyledon campanulata[5]
Cotyledon cuneata[5]
Cotyledon chrysantha
Cotyledon elisae[5]
Cotyledon galpinii[5]
Cotyledon orbiculata – pig's ear, round-leafed navelwort
Cotyledon papilaris[5]
Cotyledon tomentosa - bear's paw
Cotyledon tomentosa subsp. ladismithiensis
Cotyledon undulata - silver crown, silver ruffles
Cotyledon velutina[5]
Cotyledon woodii[5]
References

Mort, Mark E.; Levsen, Nicholas; Randle, Christopher P.; Van Jaarsveld, Ernst; Palmer, Annie (July 2005). "Phylogenetics and diversification of Cotyledon (Crassulaceae) inferred from nuclear and chloroplast DNA sequence data". American Journal of Botany. 92 (7): 1170–1176. doi:10.3732/ajb.92.7.1170. Retrieved 17 August 2021.
"Cotyledon orbiculata L." South African National Biodiversity Institute.
"Genus: Cotyledon". Biodiversity Explorer.
Dyer, R. Allen (1975). The Genera of Southern African Flowering Plants. ISBN 0-621-02854-1.
Plants of southern Africa: Names and distribution (Memoirs van die Botaniese Opname van Suid-Afrika). Pretoria: National Botanical Institute. 1993. ISBN 1-874907-03-X.
Paterson-Jones, Colin; Manning, John (2008). Field Guide to Fynbos. Cape Town: Struik Publishers. ISBN 1-77007-265-9.
Watt, John Mitchell; Breyer-Brandwijk, Maria Gerdina (1962). The Medicinal and Poisonous Plants of Southern and Eastern Africa (2nd ed.). E & S Livingstone.