Notes by Butcher May 2011.
Taxonomically speaking Schlumbergera bridgesii (Lem) Loefgr.) is treated as a synonym of S. truncata. However, this is one area of the Rhipsalidanae where hybrids abound. Regrettably, there is no International Cultivar Registration Authority for this group, so hybridists and the nursery trade have had no direction to follow the ICNCP (International Code of Nomenclature of Cultivated plants). The following gives an up-to-date summary of the situation.

Holiday Cactus in Wikipedia 7 May 2011.

The common holiday cacti (Thanksgiving Cactus, Christmas Cactus, Easter Cactus) comprise several closely related species in the genus Schlumbergera or possibly Hatiora gaertneri, often called Zygocactus in older works. Commonly cultivated, numerous cultivars have been produced ranging from red, pink, and peach to white and can appear in massive numbers on a single plant. They are originally forest cacti, growing as epiphytes at elevations between 1000 and 1700 meters (3300 to 5600 feet) above sea level in the Organ Mountains north of Rio de Janeiro in southeast Brazil, South America.

They are called Flor de Maio (May Flower) in Brazil.

Many modern holiday cactus cultivars are hybrids between Schlumbergera truncata and S. russelliana, first hybridized about 150 years ago in England.

Holiday cactus (Schlumbergera and Hatiora hybrids) include:

  • Christmas Cactus, (S. bridgesii, S. x buckleyi, Epiphyllum x buckleyi)
  • Thanksgiving Cactus, Yoke Cactus, Linkleaf Cactus, Crab Cactus, Claw Cactus, (S.
    , formerly Zygocactus truncatus)
  • Easter Cactus, (Rhipsalis gaertneri or Hatiora gaertneri - formerly Rhipsalidopsis

Easter Cactus are easily distinguished by having a different flower and a different flowering period. But what is the differences between Thanksgiving and Christmas Cactus other than the earlier flowering of the hybrid compared to the ‘Christmas’ flowering of the species. Anyone who has grown these hybrids knows that there is a range in the flowering period and it would be very rare indeed for anyone to be growing the true species which could only be relied upon if it has accurate provenance.

Uncontrolled hybridisation within the genus Schlumbergera and even possible bigeneric, means we are only guessing as to parentage. It does appear that the most likely species involved are S. russelliana and S. truncata.

If you are an optimist we may see – one day- the disappearance of Latin names and the appearance of proper anglicised names under Genera names, for man-made hybrids as recommended under the ICNCP rules since 1950!