Until around 1808, the then Portuguese colony of Brazil was isolated from the outside world. The flora and fauna were almost unknown and Brazil was largely unexplored. With the flight of the Portuguese court to Brazil, before the Napoleonic wars in 1807, this began to change. Thanks to the predominantly European explorers, our knowledge about the plant world of Brazil grew rapidly. One of the plants discovered and described at the beginning of the 19th century was Epiphyllum truncatum in 1819, today’s Schlumbergera truncata. Epiphyllum russellianum = Schlumbergera russelliana followed in 1839, then Cereus microsphaericus = Schlumbergera microsphaerica (non Cereus obtusangulus = Schlumbergera obtusangula) in 1890, and in 1905 Epiphyllum opuntioides = Schlumbergera opuntioides. After more than 70 years Schlumbergera orssichiana was described in 1978 and Schlumbergera kautskyi in 1991.
In 1858 Charles Lemaire created the genus Schlumber-gera, named after the French cactus collector Frédéric Schlumberger with the only species Schlumbergera epiphylloides, today’s S. russelliana. In 1890 Karl Schumann created the genus Zygocactus for Epiphyllum truncatum, as this species has zygomorphic flowers, whereas Schlumbergera russelliana has radiosymmetrical flowers. Alwin Berger created the genus Epiphyllanthus in 1905, because he was of the opinion that the areoles on the segments of some taxa would make this necessary. In 1913 Nathaniel Britton and Joseph Rose transferred Epiphyllum russellianum into the genus Schlumbergera, in 1953 Reid Moran combined Epiphyllum truncatum to Schlumbergera truncata, in 1969 David Hunt transferred Epiphyllum opuntioides to Schlumbergera opuntioides, and finally in 1992 P. V. Heath combined Cereus microsphaericus to Schlumbergera microsphaerica.
In 1884, Eduard von Regel described Epiphyllum russellianum var. gaertneri, a taxon that was raised to species level in 1889 and combined to Schlumbergera by Britton & Rose in 1913. In 1925 combined as Rhipsalis, in 1929 as Epiphyllopsis (Alwin Berger), in 1953 by Moran to Rhipsalidopsis and finally in 1987 by Wilhelm Barthlott to Hatiora, the classification of this species remained unclear for many years. DNA research by Alice Calvente et al. (2011) and Nadja Korotkova et al. (2011) did not yield any clear results. Calvente et al. argue for an extended genus Schlumbergera (Schlumbergera sensu lato), which includes Hatiora (partially) and Rhipsalidopsis. Korotkova et al. however recognize Rhipsalidopsis as a genus again.
The same applies to Hatiora epiphylloides and its subspecies bradei. Therefore Calvente et al. (2011) recombined it to Schlumbergera lutea and Schlumbergera lutea subsp. bradei. Although Korotkova et al. have the same molecular findings on this species as Calvente et al., they plead for the retention of the old classification due to the flower morphology deviating from Schlumbergera sensu stricto.
Rhipsalis rosea described in 1912 was the only species in 1923 that Britton & Rose placed in the genus Rhipsalidopsis before Wilhelm Barthlott transferred it to Hatiora in 1987. The DNA investigations of Calvente et al. and Korotkova et al. have shown the same results as for Epiphyllum russellianum var. gaertneri. Following their logic, Calvente et al. have combined the species to Schlumbergera rosea, while Korotkova et al. address it as Rhipsalidopsis rosea.
For the list presented here, the following taxonomy is taken as a basis:
Schlumbergera lutea subsp. lutea
Schlumbergera lutea subsp. bradei