''Schlumbergera truncata'', the false Christmas cactus, is a species of

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

in the family

Cactaceae A cactus (, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word ''cactus'' derives, through Latin, from the Ancient Greek ...

. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to a small area of the coastal mountains of south-eastern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

where its natural

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s are subtropical or tropical moist

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

s. It is the parent or one of the parents of the houseplants called Christmas cactus, Thanksgiving cactus or zygocactus, among other names.

Description

''Schlumbergera truncata'' resembles other species of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Schlumbergera ''Schlumbergera'' is a small genus of cacti with six to nine species found in the coastal mountains of south-eastern Brazil. These plants grow on trees or rocks in habitats that are generally shady with high humidity, and can be quite differen ...

'' in that it has leafless green stems which act as

photosynthetic Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in c ...

organs. The stems (

cladode Phylloclades and cladodes are flattened, photosynthetic shoots, which are usually considered to be modified branches. The two terms are used either differently or interchangeably by different authors. ''Phyllocladus'', a genus of conifer, is name ...

s) are composed of strongly flattened segments, which have two or three "teeth" of varying shapes along their edges and at the ends. The ends of the stems are "cut off" (truncated) rather than pointed. Individual segments are about long by wide. Special structures characteristic of cacti, called "

areole In botany, areoles are small light- to dark-colored bumps on cacti out of which grow clusters of spines. Areoles are important diagnostic features of cacti, and identify them as a family distinct from other succulent plants. Gordon Rowley - W ...

s", occur between two teeth at the end of segments. The areoles, which have brown wool and bristles up to long, are where the flower buds appear. The flowers are held at a constant angle somewhat above the horizontal with the higher side different from the lower side (

zygomorphic 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 ...

, specifically bilaterally symmetrical). The flowers are about long by across. There are six to eight

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s, which may be of various colours, including shades of red, orange, pink and white. The outer tepals (those at the base of the flower) are shorter and bent backwards, the inner tepals are longer and fused together at the base to form a floral tube; nectar is produced at the base of this tube. The lower inner petals are bent backwards so that the upper inner petals appear longer. Plants flower in the autumn: around May in their natural habitat, in October to November in cultivation in the Northern Hemisphere; short days and long nights are necessary to induce flowering. A characteristic of the genus ''Schlumbergera'' is that the many

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s are arranged in two series: the inner stamens form a ring around the style; the outer stamens arise from the floral tube. The filaments of the stamens are white, the anthers and pollen being yellow. The style has six to eight lobes at its end and is dark red. When ripe, the fruit is red, pear-shaped, and about long or exceptionally up to long. The shiny seeds are black, each with a diameter of about .

Taxonomy

The epithet ''truncata'' means "abruptly cut off", and refers to the shape of the ends of the stems. The species was first properly named for science by Haworth in 1819 as ''Epiphyllum truncatum''. His name was based on living specimens growing at the

Royal Botanic Gardens, Kew Royal Botanic Gardens, Kew is a non-departmental public body in the United Kingdom sponsored by the Department for Environment, Food and Rural Affairs. An internationally important botanical research and education institution, it employs 1,100 ...

in 1818. (However these do not appear to have been preserved, so an illustration published by W.J. Hooker in 1822 was designated as the "neotype" by N.P. Taylor.) Like others in the genus, the species was transferred to ''Zygocactus'' by Schumann in 1890, and then to ''Schlumbergera'' by Moran in 1953. Some other names in the genus ''Epiphyllum'' are now considered to be synonyms of ''S. truncata''. Synonyms include: *''Cactus truncatus'' Hooker, nomen nudum *''Epiphyllum truncatum'' Haw. *''Cactus truncatus'' (Haw.) Link *''Cereus truncatus'' (Haw.) Sweet *''Zygocactus truncatus'' (Haw.) K.Schum. *''Epiphyllum altensteinii'' Pfeif. *''Zygocactus altensteinii'' (Pfeif.) K.Schum. *''Epiphyllum delicatum'' N.E.Br. *''Zygocactus delicatum'' (N.E.Br.) Britton & Rose *''Epiphyllum ruckeri'' Paxton ''Epiphyllum bridgesii'' Lem., ''Schlumbergera bridgesii'' (Lem.) Loefgr. and ''Epiphyllum ruckerianum'' sensu Lem. have sometimes been treated as synonyms of ''S. truncata'', but are regarded by David Hunt as synonyms of the hybrid ''S.'' × ''buckleyi''.

Distribution and habitat

''Schlumbergera truncata'' occurs only in a small area of the coastal mountains of south-east

, in the state of

Rio de Janeiro Rio de Janeiro ( , , ; literally 'River of January'), or simply Rio, is the capital of the state of the same name, Brazil's third-most populous state, and the second-most populous city in Brazil, after São Paulo. Listed by the GaWC as a b ...

, located in the southernmost part of the tropics. Sites where it has been found include the Organ Mountains (Serra dos Órgãos) in the

Parque Nacional da Serra dos Órgãos Parque is the Galician, Portuguese and Spanish word for "park", and may refer to: * Parque (TransMilenio), a metro station in Bogotá, Colombia * Parque (Lisbon Metro), in Portugal * Parque (Santurce), a subbarrio in San Juan, Puerto Rico * ...

and in the

Serra do Mar The Serra do Mar (, Portuguese for ''Sea's Ridge'' or ''Sea Ridge'') is a 1,500 km long system of mountain ranges and escarpments in Southeastern Brazil. Geography The Serra do Mar runs parallel to the Atlantic Ocean coast from the state ...

near to the city of

. Plants grow at altitudes of . Because of their altitude and proximity to the Atlantic Ocean, the coastal mountains have high humidity – warm moist air is forced upwards into higher, colder locations where it condenses. ''S. truncata'' usually grows on trees (

epiphytic An epiphyte is an organism that grows on the surface of a 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 epiphytes grow are called phoroph ...

), or on rocks ( epilythic). The native status of ''S. truncata'' has become confused because European cultivars were deliberately introduced into some areas, including the Parque Nacional da Serra dos Órgãos, by the Brazilian Agricultural Department, to compensate for over-collecting of wild plants.

Cultivation

''Schlumbergera truncata'' is mainly grown as

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...

s of the species or of its hybrids with other species of the genus, particularly ''S. russelliana''. These plants and their cultivation are discussed at ''Schlumbergera:'' Cultivation.

References

{{Taxonbar, from=Q312047 truncata Endemic flora of Brazil Flora of the Atlantic Forest Cacti of South America Taxa named by Reid Venable Moran Garden plants of South America