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"Mistletoe cactus" redirects here. This may also mean specifically Rhipsalis baccifera, or, more generally, other Rhipsalideae.
"Cactus mistletoe" is Tristerix aphylla, a Patagonian Argentinean and Chilean species of mistletoe, whose preferred hosts are two species of cactus.

Rhipsalis is a genus of flowering plants in the cactus family, typically known as mistletoe cacti. They are found in parts of Central America, the Caribbean and northern regions of South America. Additionally they inhabit isolated locations in Africa and Asia, and are the only cactus group naturally occurring in the Old World. This is the largest and most widely distributed genus of epiphytic cacti[1] (those which live on other plants without damaging them).

Rhipsalis
Rhipsalis cereuscula1PAKAL.jpg
Flowering Rhipsalis cereuscula
Scientific classification e
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Order: Caryophyllales
Family: Cactaceae
Subfamily: Cactoideae
Tribe: Rhipsalideae
Genus: Rhipsalis
Gaertn.
Species

Numerous, see text

Synonyms

The scientific name Rhipsalis derives from the Ancient Greek term for wickerwork,[2][3] referring to the plants' morphology.

HistoryEdit

The genus was described by Joseph Gaertner in 1788.[4] But when he described the plant, he had in fact not realised it was a cactus. Instead, he assumed he had found a new species of Cassytha[Note 1], a parasitic laurel from a completely different plant family.

Ecology and distributionEdit

Rhipsalis is found as pendulous epiphyte in tropical rainforests, some species may also grow epilithic or, rarely, terrestrial.[5][6][7] The genus is found widely in Central America, parts of the Caribbean and a great part of northern and central South America.[8] The center of diversity of Rhipsalis lies in the rainforests of the Mata Atlantica in southeastern Brazil.[6] It is found throughout the New World, and additionally in tropical Africa, Madagascar and Sri Lanka.[9][7] It is the only cactus with a natural occurrence outside the New World.[10]

MorphologyEdit

The morphology of Rhipsalis is very variable. The plants can grow mostly pendent, few grow more or less upright or sprawling. There are three main stem shapes: terete, angular and flattened. The stems are succulent, but the degree of succulence varies between the species. Some have very thick stems (e.g. Rhipsalis neves-armondii), whereas other have very thin, filiform stems (e.g. Rhipsalis baccifera, Rhipsalis clavata). In the majority of species, spines are missing or occur only in the juvenile stage (this is most prominent in Rhipsalis dissimilis). Rhipsalis pilocarpa has stems and fruits densely covered by bristes, making this species easily distinguishable from all other Rhipsalis. The flowers are borne lateral or apical and are actinomorphic with a varying number of perianth segments, stamens and carpels. They are small, usually about 1 cm in diameter, white or whitish in most species. Yellowish flowers occur in R. dissimilis and R. elliptica and R. hoelleri is the only Rhipsalis species with red flowers. The fruits are always berries, they are whitish or coloured pink, red or yellow. Vivipary has been observed in R. micrantha and R. baccifera.[11]

SpeciesEdit

Based on taxonomic treatment in the The New Cactus Lexicon[12], 35 species divided into five subgenera (Phyllarthrorhipsalis, Rhipsalis, Epallagogonium, Calamorhipsalis, Erythrorhipsalis) are recognised.

Recent molecular studies[7] showed paraphyly of three subgenera as previously circumscribed (Rhipsalis, Calamorhipsalis and Epallagogonium). So a new subgeneric classification of Rhipsalis with only monophyletic subgenera Rhipsalis, Calamorhipsalis and Erythrorhipsalis is proposed.[1]

NotesEdit

  1. ^ The original spelling in publication is cassutha, but this is presumably a typographical error.

ReferencesEdit

  1. ^ a b Calvente, A. (2012), "A New Subgeneric Classification of Rhipsalis (Cactoideae, Cactaceae)", Systematic Botany, 37 (4): 983–988, doi:10.1600/036364412X656455
  2. ^ Anderson (2001), p. 612
  3. ^ "Rhipsalis". Oxford Dictionaries. Oxford University Press. Retrieved 2019-01-10.
  4. ^ Gaertner, Joseph (1788), "Rhipsalis", Fruct. Sem. Pl., i: 137, doi:10.5962/bhl.title.53838
  5. ^ Anderson (2001), pp. 22–24
  6. ^ a b Korotkova, Nadja (2011), Phylogeny and evolution of the epiphytic Rhipsalideae (Cactaceae) (PDF) (PhD thesis), Bonn
  7. ^ a b c Calvente, A.; Zappi, D.C.; Forest, F.; Lohmann, L.G. (2011), "Molecular Phylogeny, Evolution, and Biogeography of South American Epiphytic Cacti", International Journal of Plant Sciences, 172 (7): 902–914, doi:10.1086/660881
  8. ^ Anderson (2001), p. 612
  9. ^ Barthlott, Wilhelm (1983), "Biogeography and Evolution in Neo- and Paleotropical Rhipsalinae (Cactaceae)" (PDF), Sonderb. Naturwiss. Vereins Hamburg, 7: 241–248
  10. ^ Anderson (2001), p. 18
  11. ^ Cota-Sánchez, J. Hugo (2004), "Vivipary in the Cactaceae: Its taxonomic occurrence and biological significance", Flora, 199 (6): 481–490, doi:10.1078/0367-2530-00175
  12. ^ Hunt (2006), pp. 253–257

LiteratureEdit

  • Anderson, Edward F. (2001), The Cactus Family, Portland, Oregon: Timber Press, ISBN 0-88192-498-9
  • Hunt, D.R., ed. (2006), The New Cactus Lexicon Text, Milborne Port: dh books, ISBN 0-9538134-5-2
  • Barthlott, W.; Taylor, N.P. (1995), "Notes towards a Monograph of Rhipsalideae (Cactaceae)", Bradleya, 13: 43–79, doi:10.25223/brad.n13.1995.a7