![]() The inner tepals – those towards the tip of the flower – are longer and in most species become progressively more fused together at the base to form a floral tube. ![]() The outer tepals – those closer to the base of the flower – are short and unconnected, and spread out or curve backwards. In those species whose flowers are held up, their angle with the horizontal is relatively constant and is characteristic of the species. The flowers either hang downwards and are almost regular (radially symmetrical or actinomorphic) or, as in most species, are held more or less horizontally with the higher side of the flower different from the lower side (radially asymmetrical or zygomorphic). In both cases, the areoles, which may have wool and bristles, are where the flower buds appear. In two species the stems are less flattened, more cylinder-shaped, and the areoles are arranged in a more or less spiral pattern all over the segments. Special structures characteristic of cacti, called " areoles", then occur at the ends of the segments of the stem. In most species the segments are strongly flattened ( cladodes), being made up of a central core with two (or more rarely three) "wings". The stems are composed of segments, which take one of two forms. They are leafless, the green stems acting as photosynthetic organs. In the wild, the species of Schlumbergera grow either on trees ( epiphytic) or on rocks ( epilithic) and can form sizeable shrubs with woody bases a height of up to 1.2 m (4 ft) has been reported for one species ( S. Truncata Group, cut in half to show its internal structure Zygomorphic flower, probably of a cultivar in the S. They generally flower later than members of the Truncata Group and are more likely to be called Christmas cactus. russelliana: stem segments with rounded, more symmetrical teeth more or less symmetrical (regular) flowers which hang down, below the horizontal and pollen which is pink. The Buckleyi Group contains all cultivars with at least some features clearly showing inheritance from S.They generally flower earlier than members of the Buckleyi Group and, although common names are not applied consistently, may be distinguished as Thanksgiving cactus, crab cactus or claw cactus. truncata: stem segments with pointed teeth flowers held more or less horizontally, usually above the horizontal, whose upper side is differently shaped from the lower side (zygomorphic) and pollen which is yellow. The Truncata Group contains all cultivars with features derived mainly from the species S.The cultivars of the Christmas cactus fall into two main groups: The Easter cactus or Whitsun cactus, until recently placed in the genus Hatiora, is also called a holiday cactus and has flowers in red, orange, pink and white. Most of the popular houseplants are cultivars of Schlumbergera, rather than species, with flowers in white, pink, yellow, orange, red or purple. In Brazil, the genus is referred to as Flor de Maio (May flower), reflecting the period in which they flower in the Southern Hemisphere. In the Northern Hemisphere, they are called Christmas cactus, Thanksgiving cactus, crab cactus and holiday cactus. Recent phylogenetic studies using DNA have led to three species of the related genus Hatiora being transferred into Schlumbergera, though this change is not universally accepted.Ĭommon names for these cacti generally refer to their flowering season. Two species have cylindrical stems more similar to other cacti. Most species of Schlumbergera have stems which resemble leaf-like pads joined one to the other and flowers which appear from areoles at the joints and tips of the stems. These plants grow on trees or rocks in habitats that are generally shady with high humidity, and can be quite different in appearance from their desert-dwelling cousins. Schlumbergera is a small genus of cacti with six to nine species found in the coastal mountains of south-eastern Brazil. Cultivar belonging to the Schlumbergera Truncata Group
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