A cactus is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 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. Although some species live in quite humid environments, most cacti live in habitats subject to at least some drought. Many live in extremely dry environments, even being found in the Atacama Desert, one of the driest places on earth. Cacti show many adaptations to conserve water. 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 leaves, enlarged stems carry out photosynthesis. Cacti are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north—except for Rhipsalis baccifera, which also grows in Africa and Sri Lanka.
An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water or from debris accumulating around it. Epiphytes take part in nutrient cycles and add to both the diversity and biomass of the ecosystem in which they occur, like any other organism. They are an important source of food for many species. Typically, the older parts of a plant will have more epiphytes growing on them. Epiphytes differ from parasites in that they grow on other plants for physical support and do not necessarily affect the host negatively. An organism that grows on another organism that is not a plant may be called an epibiont. Epiphytes are usually found in the temperate zone or in the tropics. Epiphyte species make good houseplants due to their minimal water and soil requirements. Epiphytes provide a rich and diverse habitat for other organisms including animals, fungi, bacteria, and myxomycetes.
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 or Thanksgiving cactus, among other names.
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. 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.
Epiphyllum is a genus of epiphytic plants in the cactus family (Cactaceae), native to Central America and South America. Common names for these species include climbing cacti, orchid cacti and leaf cacti, though the latter also refers to the genus Pereskia.
Disocactus is a genus of epiphytic cacti in the tribe Hylocereeae found in Central America, the Caribbean and northern South America. It should not be confused with Discocactus, which is a different genus.
Hylocereus is a former genus of epiphytic cacti, often referred to as night-blooming cactus. Several species previously placed in the genus have large edible fruits, which are known as pitayas, pitahayas or dragonfruits. In 2017, a molecular phylogenetic study confirmed an earlier finding that the genus Hylocereus was nested within Selenicereus, so all the species of Hylocereus were transferred to Selenicereus.
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.
Disocactus ackermannii is an epiphytic cactus from tropical forests in the states of Veracruz and Oaxaca, Mexico. In cultivation, it has been confused with Disocactus × jenkinsonii, a hybrid between D. phyllanthoides and D. speciosus.
Disocactus crenatus, the crenate orchid cactus, is a species of cactus and one of the most important parents in creating the epiphyllum hybrids commonly cultivated throughout the world. It is cultivated for its large white flowers.
Epiphyllum oxypetalum, the Dutchman's pipe cactus, princess of the night or queen of the night, is a species of cactus. It rarely blooms and only at night, and its flowers wilt before dawn. Though it is sometimes referred to as a night-blooming cereus, it is not closely related to any of the species in the tribe Cereeae, such as Selenicereus, that are more commonly known as nightblooming cereus. All Cereus species bloom at night and are terrestrial plants; Epiphyllum species are usually epiphytic.
Disocactus phyllanthoides, the nopalxochitl or German empress, is a species of flowering plant in the cactus family Cactaceae. It is commonly grown as an ornamental houseplant. It is one of the three major species involved in creating the widely grown epiphyllum hybrids or "epis". The others are Disocactus speciosus and Disocactus crenatus.
Selenicereus anthonyanus is a cactus species native to southern Mexico. It is grown as an ornamental because of its nocturnal flowers and unusual, leaf-like stems. Common names include fishbone cactus, rick rack cactus, zig-zag cactus and St. Anthony's rik-rak, and is sometimes referred to as an orchid cactus.
Disocactus anguliger, commonly known as the fishbone cactus or zig zag cactus, is a cactus species native to Mexico. The species is commonly grown as an ornamental for its fragrant flowers in the fall.
Platypodium elegans or the graceful platypodium is a large leguminous tree found in the Neotropics that forms part of the forest canopy. It was first described by Julius Rudolph Theodor Vogel in 1837 and is the type species of the genus. The tree has been known to grow up to 30 metres in height and have a trunk with a diameter up to 1 m at breast height. Its trunk has large holes in it, sometimes making it possible to see through the trunk. The holes provide a habitat for giant damselflies and other insects both when alive and once the tree has died and fallen over. It has compound leaves each of which is made up of 10–20 leaflets. Three new chemical compounds have been isolated from the leaves and they form part of the diet of several monkeys and the squirrel Sciurus ingrami. In Panama it flowers from April to June, the flowers contain only four ovules, but normally only one of these reaches maturity forming a winged seed pod around 10 cm long and weighing 2 g. During the dry season around a year after the flowers are fertilised, the seeds are dispersed by the wind and the tree loses it leaves. The seeds are eaten by agoutis and by bruchid beetle larvae. The majority of seedlings are killed by damping off fungi in the first few months of growth, with seedlings that grow nearer the parent trees being more likely to die. The seedlings are relatively unable to survive in deep shade compared to other species in the same habitat. Various epiphytes are known to grow on P. elegans with the cactus Epiphyllum phyllanthus being the most abundant in Panama. Despite having holes in its trunk which should encourage debris and seeds to collect, hemiepiphytes are relatively uncommon, meaning that animals are not attracted to it to feed and then defecate. It has no known uses in traditional medicine and although it can be used for timber, the wood is of poor quality.
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.
The Hylocereeae are a tribe of cacti. Most are found in the tropical forests of Central and northern South America, and are climbers or epiphytes, unlike most cacti. The tribe includes between six and eight genera in different circumscriptions. The plants known as "epiphyllum hybrids" or "epiphyllums", widely grown for their flowers, are hybrids of species within this tribe, particularly Disocactus, Pseudorhipsalis and Selenicereus, less often Epiphyllum, in spite of the common name.
Epiphyllum hybrids, epiphyllums, epicacti, or just epis, also known as orchid cacti, which are widely grown for their flowers, are artificial hybrids of species within the group of cacti placed in the tribe Hylocereeae. In spite of the common name, epiphyllum hybrids mainly involve Disocactus species instead of Epiphyllum species, though Selenicereus grandiflorus and some unconfirmed Epiphyllum species were reportedly used for hybridization. Other sources include Pseudorhipsalis in the parentage of the group.
Strophocactus wittii, synonym Selenicereus wittii, known as the Amazon moonflower, is a species of plant in the genus Strophocactus in the cactus family (Cactaceae), and is one of several species commonly called "moonflowers". It was first described in 1900 and is one of three species of cactus found in the central Amazon basin.
