''Rhipsalis'' 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 ...

epiphytic An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the

cactus A cactus (: cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae (), a family of the order Caryophyllales comprising about 127 genera with some 1,750 known species. The word ''cactus'' derives, through Latin, ...

family, typically known as mistletoe cacti. They are found in parts of Central America, the Caribbean and northern regions of South America. They also inhabit isolated locations in Africa and Asia, and are the only cactus group naturally occurring in the

Old World The "Old World" () is a term for Afro-Eurasia coined by Europeans after 1493, when they became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia in the Eastern Hemisphere, previously ...

. This is the largest and most widely distributed genus of epiphytic cacti (those which live on other plants without damaging them). The

scientific name In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''Rhipsalis'' derives from the

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

term for

wickerwork Wicker is a method of weaving used to make products such as furniture and baskets, as well as a descriptor to classify such products. It is the oldest furniture making method known to history, dating as far back as . Wicker was first documented ...

, referring to the plants'

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

Description

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 In botany, succulent plants, also known as succulents, are plants with parts that are thickened, fleshy, and engorged, usually to retain water in arid climates or soil conditions. The word ''succulent'' comes from the Latin word ''sucus'', meani ...

, but the degree of succulence varies between the species. Some have very thick stems (e.g. ''

Rhipsalis neves-armondii ''Rhipsalis'' is a genus of epiphytic 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. They also inhabit isolated location ...

''), whereas other have very thin, filiform stems (e.g. ''

Rhipsalis baccifera ''Rhipsalis baccifera'', commonly known as the mistletoe cactus, is an epiphytic cactus which originates from Central and South America, the Caribbean, and Florida. It is also found throughout the tropics of Africa and into Sri Lanka where it i ...

'', ''

Rhipsalis clavata ''Rhipsalis'' is a genus of epiphytic 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. They also inhabit isolated location ...

''). In the majority of species,

spine Spine or spinal may refer to: Science Biology * Spinal column, also known as the backbone * Dendritic spine, a small membranous protrusion from a neuron's dendrite * Thorns, spines, and prickles, needle-like structures in plants * Spine (zoology), ...

s are missing or occur only in the juvenile stage (this is most prominent in ''

Rhipsalis dissimilis ''Rhipsalis'' is a genus of epiphytic 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. They also inhabit isolated location ...

''). ''

Rhipsalis pilocarpa ''Rhipsalis pilocarpa'', the hairy-fruited wickerware cactus, is a species of flowering plant in the cactus family that is endemic to Brazil. Scarce in the wild, it is known only in a small number of isolated locations. Its status is listed as "v ...

'' has stems and fruits densely covered by bristles, making this species easily distinguishable from all other ''Rhipsalis''. The

flowers Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

are borne lateral or apical and are

actinomorphic Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts. Uncommonly, flowers may have no axis of symmetry at all, typically because their parts are spirall ...

with a varying number of

perianth The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower. It is a structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepal ...

segments,

stamens The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filamen ...

and

carpels Gynoecium (; ; : gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ...

. 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 In plants, vivipary occurs when seeds or embryos begin to develop before they detach from the parent. Plants such as some Iridaceae and Agavoideae grow cormlets in the axils of their inflorescences. These fall and in favourable circumstances t ...

has been observed in ''R. micrantha'' and ''R. baccifera''.

Taxonomy

The genus was described by Joseph Gaertner in 1788. 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 ''Cassytha'' is a genus of some two dozen species of obligately parasitic vines in the family Lauraceae. Superficially, and in some aspects of their ecology, they closely resemble plants in the unrelated genus ''Cuscuta'', the dodders.Weber ...

'',The original spelling in publication is ''cassutha'', but this is presumably a typographical error. a parasitic

laurel Laurel may refer to: Plants * Lauraceae, the laurel family * Laurel (plant), including a list of trees and plants known as laurel People * Laurel (given name), people with the given name * Laurel (surname), people with the surname * Laurel (mus ...

from a completely different plant family.

Species

In the taxonomic treatment in ''The New Cactus Lexicon'', 35 species were accepted, divided into five subgenera (''Phyllarthrorhipsalis'', ''Rhipsalis'', ''Epallagogonium'', ''Calamorhipsalis'', ''Erythrorhipsalis''). A molecular study in 2011 showed the

paraphyly Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

of three subgenera as previously circumscribed (''Rhipsalis'', ''Calamorhipsalis'' and ''Epallagogonium''). So a new subgeneric classification of ''Rhipsalis'' with only

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

subgenera ''Rhipsalis'', ''Calamorhipsalis'' and ''Erythrorhipsalis'' was proposed. Species accepted by

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

are listed below, with subgeneric placements, where given, based on Calvente (2012).

Distribution and habitat

''Rhipsalis'' is found as pendulous

epiphyte An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

in tropical rainforests, some species may also grow epilithic or, rarely, terrestrial. The genus is found widely in

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

, parts of the

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

and a great part of northern and central

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. The center of diversity of ''Rhipsalis'' lies in the rainforests of the Mata Atlantica in southeastern

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. It is found throughout the

New World The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...

, and additionally in tropical

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

and

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

. It is the only cactus with a natural occurrence outside the New World.

Notes

References

Literature

* * * * {{Taxonbar, from=Q132296 Epiphytes Cacti of South America Cacti of North America Cactoideae genera