Hatiora
Encyclopedia
Hatiora Britton & Rose is a small genus
of epiphytic cacti which belongs to the tribe Rhipsalideae
within the subfamily Cactoideae of the Cactaceae. Some Hatiora species are well known and widely cultivated ornamentals, known as Easter Cactus or Whitsun Cactus.
s growing on rocks. They occur only in the tropical rainforests of the Mata Atlântica
in south-eastern Brazil
. The plants are weakly succulent, growing upright or pendent; spines are usually missing. The flowers are borne terminally; they are actinomorphic (radially symmetrical) and are always coloured. The fruit
is a berry
.
Hatiora species have been divided into two groups or subgenera which are well differentiated by their morphology. Members of subgenus Hatiora have cylindrical stems. They grow more or less upright and become woody at the base of the stems when plants become older. The flowers are small, with a diameter of about 1 cm (0.393700787401575 in), and yellow, orange or pink. Members of subgenus Rhipsalidopsis have flattened, weakly succulent, segmented stems. The flowers of this subgenus are large and usually red or pink, but yellow in Hatiora epiphylloides.
Hatiora gaertneri and its hybrid with H. rosea, H. × graeseri, are widely grown as ornamental houseplants under the common names Easter Cactus and Whitsun Cactus.
s or lithophyte
s. However, for a long time there was confusion as to how the rhipsalid species should be divided into genera. In 1819, Haworth
described the first discovered species of the modern genus Hatiora under the name Rhipsalis salicornioides. In 1834, A.P. de Candolle recognized the distinctness of this species and transferred it to a new genus Hariota, named after Thomas Hariot, a 16th century botanist. Later a second species, H. gaertneri, was initially named as Epiphyllum russellianum var. gaertneri (Epiphyllum russellianum is now Schlumbergera russelliana
) and then in 1889 as Epiphyllum gaertneri. A third species, H. rosea, was described in 1912 as Rhipsalis rosea.
By 1923, many nomenclatural uncertainties and confusion had arisen over the name Hariota. Nathaniel Britton
and Joseph Rose
created a new name Hatiora as an anagram of Hariota. Of the species known at the time, they placed Hariota salicornioides in Hatiora along with H. cylindrica; they had already placed H. gaertneri in Schlumbergera in 1913 and left it there; and they erected a new genus, Rhipsalidopsis, for H. rosea. When two further species of the modern genus were discovered, they were placed in various genera, including the original Hariota and Rhipsalis. According to Anderson, the confusion among the Rhipsalideae was not clarified until work by Wilhelm Barthlott and Nigel Taylor in 1995. The Easter Cactus, H. gaertneri, is still referred to as Schlumbergera gaertneri in horticultural sources; the name Rhipsalidopsis gaertneri is also still in use.
The formal synonyms of the genus Hatiora are:
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of epiphytic cacti which belongs to the tribe Rhipsalideae
Rhipsalideae
The Rhipsalideae are a small tribe of cacti, comprising four genera. They grow on trees or on rocks , where they either hang down or form creeping or upright shrubs. Their flowers open in the day and remain open at night; they may be either radially symmetrical or bilaterally symmetrical...
within the subfamily Cactoideae of the Cactaceae. Some Hatiora species are well known and widely cultivated ornamentals, known as Easter Cactus or Whitsun Cactus.
Description
All Hatiora species are found as epiphytes growing on trees or (rarely) lithophyteLithophyte
Lithophytes are a type of plant that grows in or on rocks. Lithophytes feed off moss, nutrients in rain water, litter, and even their own dead tissue....
s growing on rocks. They occur only in the tropical rainforests of the Mata Atlântica
Mata Atlântica
The Atlantic Forest is a region of tropical and subtropical moist forest, tropical dry forest, tropical savanna, semi deciduous forest and mangrove forests which extends along the Atlantic coast of Brazil from Rio Grande do Norte state in the north to Rio Grande do Sul state in the south, and...
in south-eastern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
. The plants are weakly succulent, growing upright or pendent; spines are usually missing. The flowers are borne terminally; they are actinomorphic (radially symmetrical) and are always coloured. The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
is a berry
Berry
The botanical definition of a berry is a fleshy fruit produced from a single ovary. Grapes are an example. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. They may have one or more carpels with a thin covering and fleshy interiors....
.
Hatiora species have been divided into two groups or subgenera which are well differentiated by their morphology. Members of subgenus Hatiora have cylindrical stems. They grow more or less upright and become woody at the base of the stems when plants become older. The flowers are small, with a diameter of about 1 cm (0.393700787401575 in), and yellow, orange or pink. Members of subgenus Rhipsalidopsis have flattened, weakly succulent, segmented stems. The flowers of this subgenus are large and usually red or pink, but yellow in Hatiora epiphylloides.
Hatiora gaertneri and its hybrid with H. rosea, H. × graeseri, are widely grown as ornamental houseplants under the common names Easter Cactus and Whitsun Cactus.
Name and synonyms
Cacti belonging to the tribe Rhipsalideae are quite distinct in appearance and habit from other cacti, as they grow on trees or rocks as epiphyteEpiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
s or lithophyte
Lithophyte
Lithophytes are a type of plant that grows in or on rocks. Lithophytes feed off moss, nutrients in rain water, litter, and even their own dead tissue....
s. However, for a long time there was confusion as to how the rhipsalid species should be divided into genera. In 1819, Haworth
Adrian Hardy Haworth
Adrian Hardy Haworth was an English entomologist, botanist and carcinologist.He was the son of Benjamin Haworth of Haworth Hall...
described the first discovered species of the modern genus Hatiora under the name Rhipsalis salicornioides. In 1834, A.P. de Candolle recognized the distinctness of this species and transferred it to a new genus Hariota, named after Thomas Hariot, a 16th century botanist. Later a second species, H. gaertneri, was initially named as Epiphyllum russellianum var. gaertneri (Epiphyllum russellianum is now Schlumbergera russelliana
Schlumbergera russelliana
Schlumbergera russelliana is a species of plant in the Cactaceae family. It is endemic to a small area of the coastal mountains of south-eastern Brazil where its natural habitat is moist forest. It grows on trees as an epiphyte...
) and then in 1889 as Epiphyllum gaertneri. A third species, H. rosea, was described in 1912 as Rhipsalis rosea.
By 1923, many nomenclatural uncertainties and confusion had arisen over the name Hariota. Nathaniel Britton
Nathaniel Lord Britton
Nathaniel Lord Britton was an American botanist and taxonomist who founded the New York Botanical Garden in the Bronx, New York. Britton was born in New Dorp in Staten Island, New York...
and Joseph Rose
Joseph Nelson Rose
Joseph Nelson Rose was an American botanist. He was born in Union County, Indiana. His father died serving during the Civil War when Joseph Rose was a young boy. He later graduated from high school in Liberty, Indiana....
created a new name Hatiora as an anagram of Hariota. Of the species known at the time, they placed Hariota salicornioides in Hatiora along with H. cylindrica; they had already placed H. gaertneri in Schlumbergera in 1913 and left it there; and they erected a new genus, Rhipsalidopsis, for H. rosea. When two further species of the modern genus were discovered, they were placed in various genera, including the original Hariota and Rhipsalis. According to Anderson, the confusion among the Rhipsalideae was not clarified until work by Wilhelm Barthlott and Nigel Taylor in 1995. The Easter Cactus, H. gaertneri, is still referred to as Schlumbergera gaertneri in horticultural sources; the name Rhipsalidopsis gaertneri is also still in use.
The formal synonyms of the genus Hatiora are:
- Hariota A.DC., in part, non Adans.
- Rhipsalidopsis Britton & Rose
- Epiphyllopsis (A.Berger) Backeb. & F.M.Knuth
- Pseudozygocactus Backeb.
Subgeneric classification and species
Based on the latest taxonomic treatments of the genus by Barthlott & Taylor and Hunt, Hatiora is divided into two subgenera with six accepted species, plus a hybrid created in cultivation.- Subgenus Hatiora
- Hatiora cylindrica Britton & Rose
- Hatiora herminiae (Porto & A.Cast.) Backeb. ex Barthlott
- Hatiora salicornioides (Haworth) Britton & Rose ex L.H.Bailey
- Subgenus Rhipsalidopsis
- Hatiora epiphylloides (Porto & Werderm.) Buxb.
- Hatiora gaertneri (Regel) Barthlott
- Hatiora rosea (Lagerh.) Barthlott
- Hatiora × graeseri (Werderm.) Barthlott ex D.R.Hunt, a hybrid of H. gaertneri and H. rosea