Easter cactus

Description

Schlumbergera gaertneri, formerly Hatiora gaertneri, is a species of epiphytic cactus which belongs to the tribe Rhipsalideae within the subfamily Cactoideae of the Cactaceae. Together with the hybrid with S. rosea, Schlumbergera × graeseri, it is known as Easter cactus or Whitsun cactus and is a widely cultivated ornamental plant. It has received the Royal Horticultural Society's Award of Garden Merit. Schlumbergera gaertneri is found in southeastern Brazil, in Paraná and Santa Catarina, at altitudes of 350–1,300 m (1,100–4,300 ft). As with other species of the genus, S. gaertneri grows on trees (epiphytic) or less often rocks (lithophytic) in sub-tropical rain forest. With maturity, it develops into a branching pendant leafless shrub with a woody base. The stems are made up of segments, most of which are flattened and which are the photosynthetic organs (cladodes) of the plant. Younger segments are dullish green, 4–7 cm (1.6–2.8 in) long and 2–2.5 cm (0.8–1.0 in) wide, with small notches on the margins. Structures characteristic of cacti, called areoles, form in these notches. Flowers form from areoles at the ends of the stems. These are scarlet in colour, 4–5 cm (1.6–2.0 in) long, radially symmetrical (actinomorphic), opening to a funnel shape with a maximum diameter of about 4–7.5 cm (1.6–3.0 in). Red oblong fruits form after the flowers are fertilized. Although cacti belonging to the tribe Rhipsalideae are quite distinct in appearance and habit from other cacti, as they grow on trees or rocks as epiphytes or lithophytes, for a long time there has been confusion as to how the species should be placed into genera. Schlumbergera gaertneri was first described in 1884 by Eduard von Regel as the variety gaertneri of Epiphyllum russellianum (now Schlumbergera russelliana). The name honours one of the Gaertner family, early settlers in Blumenau, Brazil. In 1889, William Watson elevated it to the full species E. gaertneri and in 1913, Nathaniel Britton and Josephy Rose transferred it to Schlumbergera as S. gaertneri. The relationship to S. russelliana was based on the appearance of the stems, made up of somewhat flattened segments with small teeth, and the radially symmetrical shape of the flowers.