Rebutia

Rebutia
Rebutia muscula in flower
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Core eudicots
Order:	Caryophyllales
Family:	Cactaceae
Subfamily:	Cactoideae
Tribe:	Trichocereeae
Genus:	Rebutia K.Schum.
Species
Rebutia arenacea Rebutia canigueralii Rebutia fabrisii Rebutia fiebrigii Rebutia marsoneri Rebutia mentosa Rebutia minuscula Rebutia muscula Rebutia narvaecensis Rebutia neocumingii Rebutia pseudodeminuta Rebutia pygmaea Rebutia spegazziniana Rebutia steinbachii Rebutia steinmannii Rebutia krainziana etc.

Rebutia K. Schum. is a genus in the family Cactaceae, native to Bolivia and Argentina.

It was designated in 1895 by Karl Moritz Schumann^[1] and named after Pierre Rebut (1828-1898), a French cactus nurseryman. The type species is R.minuscula, which has been in cultivation since 1887.^[2] These are generally small, colorful cacti, globular in form, which freely produce flowers that are relatively large in relation to the body. They have no distinctive ribs, but do have regularly arranged small tubercles. They are considered fairly easy to grow and they may produce large quantities of seeds that germinate freely around the parent plant.

Synonymy

There has been considerable debate about the extent of the genus. In the middle of the twentieth century there was a tendency to separate groups of plants within Rebutia as new genera, e.g. Mediolobivia, whereas towards the end of the century the reverse tendency predominated, with genera previously regarded as separate, such as Weingartia, being subsumed within Rebutia. At the beginning of the twenty-first century there was a broad consensus, as reflected in the list of Vascular Plant Families and Genera maintained at the Royal Botanic Gardens, Kew, that the following genera should be regarded as synonyms of Rebutia:

Aylostera Speg. Bridgesia Backeb. Cylindrorebutia Fric & Kreuz. Digitorebutia Fric & Kreuz. Echinorebutia Fric

Eurebutia Fric Gymnantha Y.Itô Mediolobivia Backeb. Mediorebutia Fric Neogymnantha Y.Itô

Reicheocactus Backeb. Setirebutia Fric & Kreuz. Spegazzinia Backeb. Sulcorebutia Backeb. Weingartia Werderm.

(The generic names Bridgesia, Spegazzinia, Echinorebutia, Eurebutia, Mediorebutia, Neogymnantha and Setirebutia are invalid, the first two because they are homonyms of Bridgesia Bert. ex Cambess. and Spegazzinia Saccardo respectively, the remainder for lack of any valid publication. Some of these are nevertheless valid names for subdivisions of the genus.) However, more recent research has indicated that the genus Rebutia so defined is polyphyletic:^[3] species formerly classified as Weingartia, Sulcorebutia and Cintia Kníže & Říha show a close relationship to each other and to species of Rebutia with naked pericarpels, including the type species R.minuscula, and it is proposed that they should be retained within the genus. However, species with hairy or bristly pericarpels form a separate, more distantly related clade and it is proposed that these should be excluded. The latter should presumably now be reclassified as Aylostera.

The number of species is similarly debatable, because of disagreement both over what constitutes the genus and what constitutes a species. A very large number plants that that have circulated as species of Rebutia are now generally regarded as varieties, forms or synonyms of others.^[4] E. F. Anderson recognised forty-one species.^[5]

Gallery

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  Rebutia arenacea

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  Rebutia heliosa

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  Rebutia minuscula

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  Rebutia narvaecensis

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  Rebutia neocumigii

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  Rebutia pygmaea

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  Rebutia steinbachii

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  Rebutia spinosissima

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  Several Rebutia cactuses

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  Several Rebutia cactuses

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  Several Rebutia cactuses

Notes

1. ^ Monatsschrift für Kakteenkunde, 5: 102, 1895
2. ^ N. L. Britton, J. N. Rose, The Cactaceae, Washington, 1920, vol.III, p.45.
3. ^ Christiane M. Ritz, Ludwig Martins, Rainer Mecklenburg, Vadim Goremykin and Frank H. Hellwig, "The molecular phylogeny of Rebutia (Cactaceae) and its allies demonstrates the influence of paleogeography on the evolution of South American mountain cacti", American Journal of Botany. 2007;94:1321-1332
4. ^ Cf. the list of approximately two hundred names under Rebutia (not to mention those given under other genera) provided in B. Fearn and L. Pearcy, The Genus Rebutia, 1895-1981, Matlock: Abbey Brook, 1981, pp.60-71.
5. ^ Edward F. Anderson, The Cactus Family, Portland, Oregon: Timber Press, 2001, pp.599-611.

Further reading

• Cacti , Succulents and Tropical Plants edited by Nicky Hayden. Marshall Cavendish Ltd, (1980).
• Rebutia Names and Identity
• The species list is compiled from cactiguide.com, which is in turn referenced from several books which are listed on that site. The principal book listed there is The Cactus Family by Edward F. Anderson, (2001).