A cactus is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1,750 known species of the order Caryophyllales. The word cactus derives, through Latin, from the Ancient Greek word κάκτος (káktos), a name originally used by Theophrastus for a spiny plant whose identity is now not certain. Cacti occur in a wide range of shapes and sizes. They are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north, with the exception of Rhipsalis baccifera, which is also found in Africa and Sri Lanka. Cacti are adapted to live in very dry environments, including the Atacama Desert, one of the driest places on Earth. Because of this, cacti show many adaptations to conserve water. For example, almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the only part of most cacti where this vital process takes place. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. In the absence of true leaves, cacti's enlarged stems carry out photosynthesis.
Schlumbergera truncata, the false Christmas cactus, is a species of plant in the family Cactaceae. It is endemic to a small area of the coastal mountains of south-eastern Brazil where its natural habitats are subtropical or tropical moist forests. It is the parent or one of the parents of the houseplants called Christmas cactus, Thanksgiving cactus or zygocactus, among other names.
In botany, areoles are small light- to dark-colored bumps on cacti out of which grow clusters of spines. Areoles are important diagnostic features of cacti, and identify them as a family distinct from other succulent plants. The spines are not easily detachable, but on certain cacti, members of the subfamily Opuntioideae, smaller, detachable bristles, glochids, also grow out of the areoles and afford additional protection.
Schlumbergera is a small genus of cacti with six to nine species found in the coastal mountains of south-eastern Brazil. 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. 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. Two species have cylindrical stems more similar to other cacti.
Rhipsalis is a genus of epiphytic flowering plants in the cactus family, typically known as mistletoe cacti. They are found in parts of Central America, the Caribbean and northern regions of South America. They also inhabit isolated locations in Africa and Asia, and are the only cactus group naturally occurring in the Old World. This is the largest and most widely distributed genus of epiphytic cacti.
Hatiora is a small genus of epiphytic cacti which belongs to the tribe Rhipsalideae within the subfamily Cactoideae of the Cactaceae. Recent taxonomic studies have led to the three species formerly placed in subgenus Rhipsalidopsis being removed from the genus, including the well known and widely cultivated ornamental plants known as Easter cactus or Whitsun cactus.
Rhipsalidopsis is a small genus of flowering plant in the family Cactaceae, native to southern Brazil. Like other members of the tribe Rhipsalideae, its species are epiphytes, growing on trees.
Rhipsalis baccifera, commonly known as the mistletoe cactus, is an epiphytic cactus which originates from Central and South America, the Caribbean, and Florida. It is also found throughout the tropics of Africa and into Sri Lanka where it is known in Sinhala as nawahandi (නවහන්දි). This is the only cactus species naturally occurring outside the Americas. One hypothesis is that it was introduced to the Old World by migratory birds, long enough ago for the Old World populations to be regarded as distinct subspecies. An alternative hypothesis holds that the species initially crossed the Atlantic Ocean on European ships trading between South America and Africa, after which birds may have spread it more widely.
Rhipsalis pilocarpa, the hairy-fruited wickerware cactus, is a species of flowering plant in the cactus family that is endemic to Brazil. Scarce in the wild, it is known only in a small number of isolated locations. Its status is listed as "vulnerable" by the IUCN Red List. However, it is cultivated as an ornamental houseplant and as such has gained the Royal Horticultural Society's Award of Garden Merit.
Schlumbergera kautskyi is a species of plant in the family Cactaceae. It is endemic to a small area of the coastal mountains of south-eastern Brazil where its natural habitat is rocky areas. It is threatened by habitat loss. It is in the same genus as the popular houseplant known as Christmas cactus or Thanksgiving cactus.
Schlumbergera opuntioides is a species of plant in the family Cactaceae. It is endemic to the coastal mountains of south-eastern Brazil where its natural habitats are humid forests and rocky areas. It is threatened by habitat loss. It is in the same genus as the popular house plant known as Christmas Cactus or Thanksgiving Cactus.
Schlumbergera orssichiana is a species of plant in the family Cactaceae. 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. It is in the same genus as the popular houseplant known as Christmas cactus or Thanksgiving cactus.
Schlumbergera russelliana is a species of plant in the family Cactaceae. 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. It is one of the parents of many of the popular houseplants known as Christmas cactus or Thanksgiving cactus.
The Rhipsalideae are a small tribe of cacti, comprising four or five genera. They grow on trees (epiphytes) or on rocks (lithophytes), 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 (regular) or bilaterally symmetrical (zygomorphic). The fruits are berry-like, fleshy with smallish seeds.
Rhipsalidopsis gaertneri, synonyms Schlumbergera gaertneri and 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 R. rosea, Rhipsalidopsis × graeseri, it is known, in English speaking countries in the Northern Hemisphere, 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.
Rhipsalis mesembryanthemoides is a cactus in the genus Rhipsalis of the family Cactaceae. The first description was in 1821 by Adrian Hardy Haworth. The shoots are reminiscent of the plants of the genus Mesembryanthemum, hence the epithet mesembryanthemoides.
Rhipsalidopsis rosea, synonyms Hatiora rosea and Schlumbergera rosea, is a species of flowering plant in the family Cactaceae, native to south Brazil. It was first described, as Rhipsalis rosea, by Gustaf Lagerheim in 1912. It is one of the parents of the hybrid Rhipsalidopsis × graeseri, grown as the Easter or Whitsun cactus.
Schlumbergera lutea, synonym Hatiora epiphylloides, is a species of flowering plant in the family Cactaceae, subfamily Cactoideae, native to southeast Brazil. It is a shrubby epiphyte, with flattened stems and bright yellow flowers.
Hatiora cylindrica is a species of often epiphytic cactus in the tribe Rhipsalideae within the subfamily Cactoideae. It is native to east Brazil, where it grows in a variety of habitats, including moist forest, dunes and coastal rocks.
Hatiora herminiae is a species of flowering plant in the tribe Rhipsalideae, family Cactaceae. It grows as an epiphyte in cloud forests in Southeast Brazil.
