Sempervivoideae

Sempervivoideae is the largest of three subfamilies in the Saxifragales family Crassulaceae, with about 20–30 genera with succulent leaves. Unlike the two smaller subfamilies, it is distributed in temperate climates.

Sempervivoideae
Sempervivum tectorum
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Saxifragales
Family: Crassulaceae
Subfamily: Sempervivoideae
Arn[1]
Type genus
Sempervivum
Tribes
Synonyms

Description

Succulent leaved plants. Unlike the other two smaller subfamilies, which are highly derived, Sempervivoideae retain the basic features of the family Crassulaceae.[3] The Sempervivoideae contain many familiar horticultural plants, such as Sedum.[4]

Taxonomy

Sempervivoideae has taxonomic priority over its synonym, Sedoideae,[5] and is related to the other Crassulaceae subfamilies, as shown in this cladogram;

Cladogram of evolutionary lines in Crassulaceae[3]
Crassulaceae
 

Crassuloideae

 
 
 

Kalanchoöideae

 
 

Sempervivoideae

 
 
 

Subdivisions (tribes)

Six clades within Crassulaceaeare are segregated into the five tribes with about thirty genera.[3]

Clades and tribes within Sempervivoideae
CladeTribe
AcreSedeae
Leucosedum
AeoniumAeonieae
SempervivumSemperviveae
RhodiolaUmbiliceae
HylotelephiumTelephieae

The composition of the five tribes are: (number of genera/species);[6]

  • Telephieae (6/50)
  • Umbiliceae (4/100)
  • Semperviveae (2/75)
  • Aeonieae (3/70)
  • Sedeae (7/520)

and their relationship is shown in the cladogram:

Cladogram of Sempervivoideae tribes[3]
Sempervivoideae
 

Telephieae

 
 
 

Umbilicieae

 
 
 

Aeonieae

 
 
 

Semperviveae

 
 

Sedeae

 
 
 
 
 

However, given the difficulty of establishing a stable classification, some authors prefer larger groupings, e.g.;[7]

  • Telephinae (Telephieae, Umbilicieae)
  • Sedinae (Semperviveae, Aeonieae, Sedeae)

Semperviviae, Aeonieae and Sedeae are definable only by plesiomorphic features, with their genera all derived from within Sedum. Segregates of Sedum occur in each of these, but lack sufficient features to allow them to be allocated to definitive genera.[3][8]

Hylotelephium spectabile

Telephieae ('t Hart) Ohba and Thiede ined.

The Telephieae[lower-alpha 2] genera consist of former infrageneric taxa of Sedum, and are distributed primarily in East Asia. Defined by 5-merous flowers, free petals, flat, dentate leaves and tuberous roots or thickened rhizomes. Leaves usually in rosettes, except Hylotelephium, petals often spotted, autumn flowering. The taxonomy remains unstable, with species Orostachys embedded within both Meterostachys and Hylotelephium. It contains about 6 genera, with 50 species, including:[5][3] It is likely that diversification of the tribe occurred at the time of the formation of the Himalayas.[9]

Umbilicus intermedius

Umbiliceae Meisn.

The Umbeliceae occur mainly in temperate areas of Asia, flowering in spring to early summer, with about 4−5 genera and 100 species. Aizopsis is included by some authors in Phedimus. The genera are among those that have been segregated from Sedum, including:[3]

Sempervivum tectorum

Semperviveae Dumort.

Semperviveae have acuminate leaves and polymerous flowers. Two to three genera, derived from within Sedum, c. 275 species. Earlier treatments considered Jovibarba a section of Sempervivum[3] but has subsequently been demonstrated to be a separate genus.[4]

Aeonium aureum

Aeonieae Thiede ined.[lower-alpha 1]

Aeonieae (also referred to as the GAMA clade, for Greenovia, Aeonium, Monanthes and Aichryson),[14] whose distribution is primarily Macaronesia, have polymerous flowers, and include genera derived from within Sedum, with about 3 genera and 70 species, including:[3]

Sedeae Fr.

Sedeae is the largest of these and contains two sister clades, Leucosedum and Acre.[3] It contains about 12 genera, mainly derived from within Sedum, and 520 species. Genera are often treated as two separate clades. Of these, while the larger Acre is robust, Leucosedum remains paraphyletic.[6] The genera included are:[3]

Dudleya caespitosa

Leucosedum clade

Genera derived from European and Mediterranean Sedum subg. Gormania, with two western North American genera (Dudleya, Sedella, which are sister genera).[6]

Echeveria agavoides

Acre clade

c. 7 genera, 500 sp.

Genera
See also: List of Sempervivoideae genera

Given the monophyly demonstrated for Aeonieae and Semperviveae (as quite distinct from Sedeae), it has been recommended that those species of Sedum originally found in those tribes, be removed from the genus and reassigned. This includes Sedum series Rupestria from Semperviveae, but collectively account for only a small fraction of the genus. While restricting Sedum to Sedeae simplifies the infrafamilial structure of the genus, its species remain distributed within both clades of this tribe.[6][13][15]

Notes
  1. Reveal proposed the revised authority: Aeonieae Thiede ex Reveal[2]
  2. The name Telephieae may be illegitimate in this context, since it has been previously used as a synonym for Caryophyllaceae[2]
  3. Petrosedum is classified as Sedum series Rupestria by some authors[6]

References
  1. 1832: Botany 112.
  2. Reveal 2012.
  3. Thiede & Eggli 2007.
  4. Mort et al 2010.
  5. Gontcharova & Gontcharov 2007.
  6. Nikulin et al 2016.
  7. Gontcharova & Gontcharov 2009.
  8. Mayuzumi & Ohba 2004.
  9. Nikulin et al 2015.
  10. Ohba et al 2000.
  11. Fu et al 2004.
  12. ICN 2019.
  13. Gallo 2017.
  14. Soltis et al 2013.
  15. Gallo 2017a.

Bibliography

Books

  • Eggli, Urs, ed. (2003). Illustrated Handbook of Succulent Plants: Crassulaceae. Springer Science & Business Media. doi:10.1007/978-3-642-55874-0. ISBN 978-3-642-55874-0.
  • Thiede, J; Eggli, U (2007). "Crassulaceae". In Kubitzki, Klaus (ed.). Berberidopsidales, Buxales, Crossosomatales, Fabales p.p., Geraniales, Gunnerales, Myrtales p.p., Proteales, Saxifragales, Vitales, Zygophyllales, Clusiaceae Alliance, Passifloraceae Alliance, Dilleniaceae, Huaceae, Picramniaceae, Sabiaceae. pp. 83–119. ISBN 978-3540322146. (full text at Research Gate)

Articles

Websites

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