Genus: Cacti
Acanthocalycium
Acanthocalycium
Genus of cacti endemic to Argentina with four accepted species. The globular to short-cylindrical, very spiny stems produce tubular flowers with scales and spines on the floral tube — a character giving the genus its name ("spiny calyx," from Greek akanthos + kalyx). They inhabit arid and semi-arid zones of the Andean provinces of central-northwestern Argentina, especially on rocky slopes and ravines between 500 and 2,500 m.
Acanthocereus
Acanthocereus
Genus of cacti with columnar or scrambling stems and well-defined angular ribs (3–5 ribs), long spines, large white nocturnal flowers, and edible red fruits. Widely distributed across tropical America, from southern Florida to northern South America, in tropical coastal habitats, dry scrublands, and riverbanks.
Acharagma
Acharagma
Genus of small globular cacti endemic to northeastern Mexico, with two accepted species. Related to Escobaria and Mammillaria, they are distinguished by unique floral and seed characters: seeds with a well-developed aril and flowers emerging from the apex. They inhabit arid limestone slopes of the Chihuahuan Desert and the mountain ranges of northeastern Mexico.
Ancistrocactus
Ancistrocactus
Small globular cacti from southern Texas and northeastern Mexico, with conical tubercles and strongly hooked central spines — hence the name, from the Greek ankistron (hook). They inhabit xerophytic scrublands on calcareous or clay soils, often in areas of seasonal rainfall. A small genus, with only two widely recognized species, both with restricted distribution and under pressure from illegal collection and habitat loss.
Ariocarpus
Ariocarpus
Genus of living rock cacti endemic to Mexico and the extreme southern tip of Texas, with 6–7 accepted species. Their flattened or hemispherical bodies, with triangular or leaf-like tubercles and no spines in maturity, mimic rock and soil, making them extraordinarily cryptic in their habitat. Lifespan of centuries, extremely slow growth, and high vulnerability to collection. All species are protected under CITES Appendix I.
Armatocereus
Armatocereus
Genus of columnar or arborescent cacti with segmented stems and marked spiny ribs, native to the Pacific Andean slopes. Their annual segments are clearly distinguishable on mature stems, giving them an unmistakable articulated appearance. White to pinkish flowers, nocturnal or crepuscular. They produce edible fleshy fruits known as pitajayas in local communities. They inhabit zones from arid coastal areas to mountain slopes of the western Andean cordillera in Ecuador, Peru, and Colombia.
Arrojadoa
Arrojadoa
Genus of slender, bamboo-like columnar cacti from the semi-arid caatinga of northeastern Brazil, with 5–6 accepted species. Their stems produce at the end of each growing season a pseudocephalium — an annular crown of spines and woolly hairs — from which the tubular flowers in red to deep pink emerge. They inhabit the caatinga and rupestrian fields of northeastern Brazil. Named in honor of Brazilian engineer and botanist Miguel Arrojado Ribeiro Lisboa (1872–1932).
Arthrocereus
Arthrocereus
Genus of slender and articulated columnar cacti endemic to the rupestrian grasslands and quartzitic outcrops of the state of Minas Gerais, Brazil, with 3–4 accepted species. Their thin, very spiny stems produce white to pinkish flowers that open at night, often fragrant, with a very long style. Related to Disocactus and the epiphytic clade, but terrestrial. They inhabit crevices of quartzitic rocks at elevations of 900–2,000 m.
Astrophytum
Astrophytum
Genus of globular to short-cylindrical cacti from northern Mexico and the extreme southern tip of Texas, with 4–5 accepted species. They are distinguished by their spineless bodies in the most well-known species (though some have spines), covered in small white stellate scales or hairs giving them a silvery or mottled appearance. Yellow flowers with red or orange center, diurnal and large relative to the plant body. Highly prized in cactus collections for their perfect geometric form and their long history of breeding in Japan, where hundreds of cultivars have been created.
Austrocactus
Austrocactus
Genus of small globular to ovoid-cylindrical cacti from southern Patagonia and the southern Andes, with 4 accepted species. They are the southernmost cacti in the world, capable of withstanding hard frosts and snowfall. Their central spines are frequently hooked at the tip. They inhabit arid Patagonian steppes and Andean slopes from Mendoza to southern Patagonia in Argentina, and in Chile from Atacama to Coquimbo.
Austrocylindropuntia
Austrocylindropuntia
Genus of cylindrical opuntias from the Andes and Pacific coasts of South America, with some 10–12 accepted species. Distinguished from Opuntia by their clearly cylindrical (not flattened) stems and persistent rudimentary leaves. They occupy an extraordinarily wide altitudinal range, from the arid Pacific coasts to the high-Andean summits (4,500 m), including the singular high-Andean opuntias covered in woolly hairs (A. floccosa) and coral-like opuntias with flattened segments (A. clavarioides). Widely used as living fences and as a source of fruits in the Andes.
Aztekium
Aztekium
Genus of three extremely slow-growing cacti endemic to the gypsum cliffs of Nuevo León, Mexico. Their bodies have ribs with additional transverse folds that resemble the bas-reliefs of Aztec architecture, from which the genus name derives. They are the slowest-growing known cacti (millimeters per year), which, combined with habitat destruction and illegal collection, makes them extremely vulnerable. All three species are protected under CITES Appendix I.
Bergerocactus
Bergerocactus
Monotypic genus of colonial coastal cacti, native to the coastal strip of California (USA) and Baja California (Mexico). Its bright green cylindrical stems, densely covered in golden-yellow spines, grow prostrate or semi-erect on rocky coastal slopes with marine influence. The genus was established in honor of German naturalist Alwin Berger. Its only species, B. emoryi, is one of the few plants that grow on the rocky coastal cliffs of southern California.
Blossfeldia
Blossfeldia
Monotypic genus housing the world's smallest cactus, B. liliputana, whose adult body can measure just 1 cm in diameter. It lacks ribs and has flat, tiny spiral tubercles. During extreme drought it almost completely dehydrates and contracts until visually integrated with the rock, reanimating with rain (poikilohydry). Inhabits crevices of calcareous or granitic rocks in northwestern Argentina and Bolivia. Named in honor of German collector Harry Blossfeld.
Brachycereus
Brachycereus
Monotypic genus of small columnar cacti endemic to the Galápagos Islands. Its single species, the lava cactus, colonizes recent lava flows and arid coastal zones where few plants survive, frequently being the first colonizer on bare volcanic substrates.
Brasilicereus
Brasilicereus
Genus of columnar cacti from eastern Brazil, with slender stems and nocturnal tubular flowers. They grow in caatinga, cerrado and rupicolous vegetation on rocky outcrops, tolerating extended dry periods.
Brasiliopuntia
Brasiliopuntia
Genus of arborescent cacti related to Opuntia, endemic to South America. It is characterized by a main cylindrical woody trunk from which flattened cladode branches arise, creating an unusual tree-like silhouette within the subfamily Opuntioideae.
Browningia
Browningia
Genus of columnar cacti in the family Cactaceae native to the western Andes of Peru and Bolivia. Produces branched columns of imposing appearance with numerous ribs and robust spines. Its nocturnal flowers, white or pink, are large. Genus named in honour of W.E. Browning. Inhabits ravines and dry Andean valleys at moderate altitudes.
Calymmanthium
Calymmanthium
Small genus of columnar cacti from northern Peru, notable for its unusual floral structure that distinguishes it from other genera: its flowers are partially covered by bracts forming a kind of sheath or cover (hence the name, from Greek "kalymma", cover). It grows in dry inter-Andean valleys at mid-elevations.
Carnegiea
Carnegiea
Monotypic genus containing the saguaro, the largest columnar cactus in North America and an iconic symbol of the Sonoran Desert. Its imposing columns with upward-curved arms can reach 15 m in height and live more than 150 years. The genus was named in honour of philanthropist Andrew Carnegie.
Cephalocereus
Cephalocereus
Genus of tall columnar cacti native to Mexico, world-famous for its type species, the "old man cactus" (C. senilis), whose stems are completely wrapped in long white bristles mimicking an old man's hair. The fertile apical zone develops a lateral pseudocephalium of dense wool from which nocturnal flowers emerge.
Cephalocleistocactus
Cephalocleistocactus
Small genus of columnar cacti from Bolivia, with slender stems and a well-developed lateral or apical cephalium of brightly coloured (golden, reddish) wool and bristles from which cleistocereoid tubular flowers emerge. It inhabits gorges and slopes of the Bolivian Andes at mid-elevations.
Cereus
Cereus
Genus of columnar cacti in the family Cactaceae native to northern South America, the Caribbean, and Argentina/Brazil. It is one of the founding genera of the Cactaceae family, with robust, ribbed columns up to 15 m tall. Its large, white, nocturnal flowers are highly fragrant. The name Cereus (wax candle) refers to the erect columnar habit. Widely cultivated as an ornamental hedge throughout the tropical and Mediterranean world.
Cintia
Cintia
Monotypic genus of high-altitude globose cacti, endemic to the Bolivian Andes (Potosí department). Small, leafless plant extremely adapted to high-altitude conditions (4000–4500 m a.s.l.), frequent frost, and high UV radiation. Described by Říha in 1995 and dedicated to Cintia Douzet.
Cipocereus
Cipocereus
Small genus of columnar cacti endemic to the quartzite rocky outcrops (campo rupestre) of Minas Gerais, Brazil. Comprises 5–6 species characterized by striking nocturnal blue-violet to white flowers and vividly colored blue, green, or violet fruits. Described by Ritter and revised by Zappi & Taylor.
Cleistocactus
Cleistocactus
Genus of columnar to semi-pendent cacti from western South America, with ~50 accepted species distributed mainly in Bolivia, Peru, Argentina, Uruguay, Paraguay and Brazil. Characterized by narrow, closed tubular flowers (cleistocactus = "closed-flower cactus"), adapted for hummingbird pollination. Altitudinal range spans from dry inter-Andean valleys at 400 m to 3500 m a.s.l. on the Andean altiplano.
Cochemiea
Cochemiea
Genus of tuberculate cacti endemic mainly to the Baja California peninsula, Mexico. Comprises about 16 species with globose to cylindric stems, spiral tubercles, often hooked central spines, and brightly colored tubular flowers. Previously classified within Mammillaria.
Cochiseia
Cochiseia
Monotypic genus of cacti endemic to the canyons and plateaus of Utah and Colorado (Canyonlands National Park), United States. Its sole species, C. robbinsorum, is a small globose cactus with pink flowers often included in Sclerocactus.
Coleocephalocereus
Coleocephalocereus
Genus of columnar cacti endemic to Brazil, especially the rocky outcrops (campos rupestres) of Minas Gerais state and adjacent areas. Characterized by a lateral woolly and bristly pseudocephalium from which nocturnal tubular flowers emerge.
Consolea
Consolea
Genus of arborescent Caribbean opuntioids, characterized by cylindric stems (not flattened into cladodes) and long spines. They form trees up to 8 m in coastal scrub, mangroves, and tropical dry forests of the Antilles and southern Florida.
Copiapoa
Copiapoa
Genus of cacti endemic to Chile, mainly from the Atacama Desert and the northern Chilean coastal zone. Comprises more than 25 species with globose to columnar stems that survive in one of the world's most arid environments by capturing coastal fog (camanchaca). They have bluish to grayish-green epidermis and variable spines.
Corryocactus
Corryocactus
Genus of branching columnar cacti endemic to the Andes of Peru and Bolivia, with extensions to Chile and Argentina. Comprises about 25 species of strongly ribbed stems with robust spines and brightly colored diurnal flowers (orange, red, yellow). They inhabit dry inter-Andean valleys to arid high-altitude slopes.
Corynopuntia
Corynopuntia
Genus of cacti in subfamily Opuntioideae native to the southwestern North America and northern Mexico. Low-growing, shrubby or prostrate plants with cylindrical to club-shaped jointed stem segments (cladodes), spines with papery deciduous sheaths, glochids, and yellow to pink flowers. Dry or fleshy fruits with large seeds. Formerly included in Opuntia.
Coryphantha
Coryphantha
Genus of globose to cylindrical cacti in subfamily Cactoideae native to Mexico and southwestern United States. Distinguished from Mammillaria by having grooves on the tubercles connecting the apical areole with the flower in the axil between tubercles. Large yellow to pink to magenta flowers at the apex. Many species with extrafloral nectary glands in the grooves. Great conservation importance: many species endangered or threatened.
Cylindropuntia
Cylindropuntia
Genus of cacti in the subfamily Opuntioideae comprising the "chollas", plants with cylindrical, jointed stems and retrorsely barbed spines that cling to animals and humans, facilitating vegetative dispersal. Includes about 33 species native to the southwestern United States, Mexico, the Caribbean, and parts of South America.
Dendrocereus
Dendrocereus
Monotypic or near-monotypic genus of arborescent cacti endemic to Cuba, in the subfamily Cactoideae. They are the largest cacti in Cuba, with robust columnar stems forming large trees. Their nocturnal flowers are pollinated by bats. An emblematic species of the Cuban natural landscape.
Denmoza
Denmoza
Monotypic genus of columnar cacti endemic to western Argentina, in the subfamily Cactoideae. Characterized by its tubular red flowers and red or yellow spines arranged in dense areoles. Its name is an anagram of "Mendoza", Argentina.
Digitostigma
Digitostigma
Monotypic genus of cacti in the subfamily Cactoideae, endemic to northeastern Mexico. Distinguished by its elongated, finger-like tubercles giving it a "Medusa head" appearance. Recently described with a very restricted distribution.
Discocactus
Discocactus
Genus of cacti in the subfamily Cactoideae endemic to South America, mainly Brazil. Characterized by their flattened disc-like form and the development of a woolly terminal cephalium from which nocturnal, fragrant flowers emerge. Very sensitive to excess moisture and low temperatures.
Disocactus
Disocactus
Genus of epiphytic cacti in the subfamily Cactoideae, native to Mexico, Central America, and northern South America. Characterized by flattened or angled pendant stems and showy daytime flowers in red, pink, or orange tones. Formerly included many species classified in Heliocereus, Nopalxochia, and Wittia.
Eccremocactus
Eccremocactus
Small genus of epiphytic cacti in the subfamily Cactoideae, endemic to the cloud forests of Costa Rica and Panama. Characterized by their climbing or pendant habit, flattened or angled stems, and nocturnal white or cream flowers. These plants are very little known outside scientific circles.
Echinocactus
Echinocactus
Genus of globose to cylindrical cacti in the subfamily Cactoideae, native to the southwestern United States and Mexico. Characterized by prominent ribs, stout spines, and brightly colored apical flowers. In the strict POWO sense, the genus comprises only a few accepted species, the most famous being E. grusonii, the golden barrel cactus.
Echinocereus
Echinocereus
Genus of columnar to globose cacti in the subfamily Cactoideae, native to southwestern North America. Characterized by small to medium-sized stems, usually clustering into colonies, defined ribs, and large showy flowers that open during the day. Comprises approximately 70 accepted species, very popular in collections and xeric gardens.
Echinomastus
Echinomastus
Genus of small to medium-sized cacti in the subfamily Cactoideae, native to the southwestern United States and northern Mexico. Characterized by globose to cylindrical form, frequently hooked spines, and brightly colored diurnal flowers. Several species are in threatened categories due to very restricted distribution.
Echinopsis
Echinopsis
Large and diverse genus of cacti in the subfamily Cactoideae, native to South America. In the broad sense (POWO circumscription) includes former species of Trichocereus, Lobivia and other genera. Comprises everything from giant columnar cacti to miniature globose forms, all with large showy flowers, frequently nocturnal and fragrant.
Epiphyllum
Epiphyllum
Genus of epiphytic cacti in the family Cactaceae with flattened, leaf-like stems, native to humid tropical and subtropical forests of the Americas. Popularly known as "orchid cacti", they produce large, very fragrant nocturnal flowers that open for a single night. The name means "upon the leaf" referring to its flowers that seem to emerge from the phylloclades. Widely cultivated worldwide for their spectacular flowers.
Epithelantha
Epithelantha
Genus of miniature globose cacti in the family Cactaceae, native to arid zones of the southwestern United States and northern Mexico. Known as "button cacti", they are very slow-growing and produce tiny pink flowers at the apex. Characterized by their numerous short, tightly packed white spines that densely cover the entire stem surface. Highly valued in specialized cactus collections.
Eriosyce
Eriosyce
Genus of globose to cylindrical cacti in the family Cactaceae, native mainly to Chile and adjacent areas of Peru and Argentina. Groups numerous species formerly classified in Neoporteria, Pyrrhocactus, Horridocactus and other genera. Characterized by flowers in pink, red or yellow tones emerging from the woolly apex and their hollow fruits. Very representative of the arid flora of Chilean coasts and interiors, from the Atacama Desert to the Libertador region.
Escobaria
Escobaria
Genus of globose to cylindrical cacti in the family Cactaceae, native to arid and semi-arid zones of the southwestern United States, Mexico and Cuba. Very similar to Mammillaria in appearance, distinguished by producing flowers from the center of the apex (not from axillary grooves) and seeds with different surface texture. Includes species from the Great Plains, Chihuahuan Desert and arid mountain regions. Several species are rare or endemic to very restricted areas.
Espostoa
Espostoa
Genus of columnar cacti in the family Cactaceae, characterized by their dense covering of silky white hairs that gives them the appearance of the famous Peruvian "old man cactus". Native to the Andes of Peru and Ecuador, where they grow on arid slopes and ravines at medium altitude. They produce a lateral woolly pseudocephalium from which nocturnal flowers emerge. Named in honor of Peruvian botanist Nicolás E. Esposto.
Eulychnia
Eulychnia
Genus of columnar cacti in the family Cactaceae, endemic to Chile and the extreme south of Peru. One of the most representative cactus genera of the Chilean arid flora, forming "cardon forests" in coastal and interior zones. They produce white to pink flowers and locally prized edible fruits. Several species present crested and monstrose forms highly sought after in the ornamental cactus trade.
Ferocactus
Ferocactus
Genus of barrel cacti in the family Cactaceae, characterized by their robust globose to cylindrical form and imposing strong and often hooked spines. Native to arid zones of the southwestern United States and Mexico, they are the most characteristic barrel cacti of the Sonoran Desert and adjacent regions. They produce yellow, red or orange flowers at the apex of adult individuals. Some produce edible fruits used in gastronomy and confectionery.
Frailea
Frailea
Genus of small to minute cacti, generally globose to shortly cylindrical, with notable cleistogamous capacity (self-pollination without opening flowers). Native to South America (southern Brazil, Paraguay, Uruguay and northern Argentina). Tuberculate ribs, thin spines and small yellow flowers that often do not open. Prized in specialised collections for their compact size and ease of cultivation.
Geohintonia
Geohintonia
Monotypic genus of globose cacti, endemic to the Yeso Galeana Formation (gypsum substrate) in Nuevo León, Mexico. Solitary stems, globose, grey or blue-glaucous, with sharp ribs and short spines. Flowers at apex with pink flowers. Discovered and described in 1991 by Charles Glass and Ken Fitz Maurice. Critically endangered due to very restricted habitat and illegal collection.
Grusonia
Grusonia
Genus of cylindrical cacti in the family Cactaceae (subfamily Cylindropuntioideae) native to northern Mexico (especially Baja California and Sonora) and the southwestern United States. Grusonias are columnar or shrubby cacti with articulated cylindrical segments, similar to chollas (Cylindropuntia) with which they were historically confused or synonymised. They produce yellowish-green flowers and fleshy fruits. Adapted to the extreme conditions of the Sonoran Desert and Baja California deserts.
Gymnocalycium
Gymnocalycium
Genus of globose to slightly flattened cacti native to South America. Characterized by ribs divided into tubercles with a distinctive "chin" below the areole, diurnal flowers usually white, pink, or red, and lack of spines on the floral tube. Comprises over 70 species, very popular in collections.
Gymnocereus
Gymnocereus
Genus of columnar cacti from Peru and Bolivia, now largely synonymised with Weberbauerocereus or Browningia. Erect cylindrical stems, well-branched from base; numerous ribs with spiny areoles; nocturnal tubular flowers; fleshy fruits.
Gymnorebutia
Gymnorebutia
Genus segregated from Rebutia by Doweld (2000), grouping small globose cacti from Bolivia and Peru. Globose to low cylindrical bodies; spiral ribs divided into tubercles; small diurnal flowers of varied colours; very similar to Rebutia. Most current treatments synonymise them with Rebutia.
Haagea
Haagea
Monotypic genus described by Frič, now synonymised with Gymnocalycium. Globose cactus from central Argentina with typical Gymnocalycium characteristics: tuberculate ribs with chin, curved radial spines and white flowers.
Haageocereus
Haageocereus
Genus of columnar cacti from the coast and Andean slopes of Peru, with some species in Ecuador and Bolivia. Erect or scrambling cylindrical stems, densely spiny; numerous fine radial spines, robust central spines sometimes coloured; white to pink nocturnal tubular flowers; pollinated by bats and moths; very ornamental for their dense colourful spinescence.
Hamatocactus
Hamatocactus
Hamatocactus is a small genus of globose to shortly cylindrical cacti from the Chihuahuan Desert, distributed across Texas, New Mexico, and northern Mexico. Their most distinctive feature is the strongly hooked lower central spine (from Latin hamatus, hooked) that gives them their common name of fishhook cactus. Flowers are large relative to plant body, generally yellow with a red center, and the ripe fruits are reddish and ornamental. Some authors place them within Ferocactus or Thelocactus, but they form a morphologically coherent group highly valued in collections.
Harrisia
Harrisia
Harrisia is a genus of night-blooming columnar cacti distributed across the Caribbean islands, southern Florida, and eastern South America (Argentina, Uruguay, Paraguay, Brazil). Their stems are elongated, often climbing or leaning, with well-marked ribs and spiny areoles. Flowers are large, white, very fragrant, and nocturnal, followed by spherical red or orange fruits with edible white pulp. Some species are critically endangered (H. fragrans in Florida), while others (H. martinii, H. bonplandii) have become invasive in Australia, Madagascar, and other regions. H. jusbertii is widely used as grafting stock in cultivation. The genus is named after William Harris, the Jamaican botanist.
Haseltonia
Haseltonia
Haseltonia is a genus of giant columnar cacti from Mexico, distributed mainly in the Tehuacán-Cuicatlán Valley (Oaxaca and Puebla), designated a UNESCO World Heritage Site for its exceptional cactus diversity. Haseltonia plants are monumental succulent trees reaching 10–15 m in height. Their most distinctive feature is a lateral pseudocephalium — a zone of dense wool and bristles from which the nocturnal tubular flowers emerge. Morphologically close to Cephalocereus and Pachycereus, Haseltonia was separated as an independent genus based on floral characteristics and the lateral (not apical) position of the pseudocephalium.
Hatiora
Hatiora
Hatiora is a genus of epiphytic cacti from the Brazilian Atlantic Forest (Mata Atlântica), characterized by jointed, spineless stems adapted to grow on branches and mossy rocks in humid, shaded environments. Flowers are relatively small, diurnal, yellow to pink or red depending on the species. The best-known species are the Easter cactus (H. gaertneri) and H. rosea, with intensely pink flowers very popular in floriculture. Hatiora was segregated from Rhipsalis and Hariota, and is recognized as an independent genus in modern classification.
Heliabravoa
Heliabravoa
Heliabravoa is a monotypic genus of columnar cacti from Mexico established by botanist Helia Bravo-Hollis and D.K.Cox. Its single species, H. chende, is a medium columnar tree of the Tehuacán-Cuicatlán Valley (Oaxaca, Puebla, and Morelos), designated a UNESCO World Heritage Site. Morphologically it approaches Polaskia and Escontria; some authors treat Heliabravoa chende as Polaskia chende. The plants form branching columns to 8 m with nocturnal white flowers and edible reddish fruits called "chende" in Mixtec, from which the vernacular name comes.
Hildewintera
Hildewintera
Hildewintera is a genus of pendant columnar cacti from the eastern Andes of Bolivia and northwestern Argentina, named after Hildegard Winter. Its species have pendulous stems reaching 1–2.5 m in length, densely covered in soft, silky spines in golden, white, or chestnut tones. Flowers are tubular and appear laterally along the stem in colors ranging from orange to intense red. Some authors include Hildewintera within Cleistocactus, but it is frequently kept as an independent genus due to its unique growth habits. H. colademononis, the famous "monkey tail cactus," has become one of the world's most popular cacti in the last 25 years.
Hylocereus
Hylocereus
Hylocereus is a genus of climbing and epiphytic cacti from tropical and subtropical America, world-renowned for producing pitahaya or dragon fruit (H. undatus), one of the fastest-expanding tropical fruit crops of the 21st century. Their stems are generally triangular or 3–4-winged and climb via aerial roots on trees, rocks, or artificial structures. Flowers are enormous (15–30 cm), white, nocturnal, and very fragrant; they open at dusk and wither by dawn, pollinated primarily by bats and nocturnal moths. Fruits are large berries with scaly skin and white, red, or yellow flesh. Korotkova et al.'s (2017) taxonomic revision synonymized Hylocereus within Selenicereus, although Hylocereus remains widely used in agronomy and horticulture.
Jasminocereus
Jasminocereus
Jasminocereus is a monotypic genus of arborescent columnar cacti endemic to the Galápagos Islands (Ecuador), one of the most biologically unique volcanic archipelagos on Earth. Its single species, J. thouarsii, known as the Galápagos cactus or candelabra cactus, is an emblematic plant of the Galápagos ecosystem with a fascinating evolutionary history. The species evolved from a South American ancestor that colonized the islands and developed woody trunks with scaly reddish-orange bark to raise its photosynthetic pads and flowers beyond the reach of herbivorous reptiles, especially the Galápagos giant tortoises. The degree of arborization varies notably among island populations according to herbivory pressure: on tortoise-inhabited islands, stems reach 7 m; on islands without tortoises, plants remain shorter and more branching. Jasminocereus interacts closely with the Galápagos ecosystem: its flowers are visited by Darwin's finches and its fruits are a crucial food source for giant tortoises and land iguanas.
Leocereus
Leocereus
Leocereus is a small genus of slender-stemmed columnar cacti endemic to the Caatinga of northeastern Brazil, mainly in the state of Bahia and parts of Minas Gerais. The genus was named after German botanist Leo Zehntner, who worked in Brazil in the early 20th century. Its species are nocturnal cacti with erect or semi-erect stems bearing numerous ribs and large white flowers. Ecologically they are an important element of the xerophytic vegetation of the Brazilian semi-arid region, an exceptionally rich biome in endemic Cactaceae.
Lepismium
Lepismium
Lepismium is a genus of neotropical epiphytic cacti closely related to Rhipsalis, from which it is mainly distinguished by having flowers in lateral areoles along the stem (not only terminal ones) and by frequently producing more than one flower per areole. They inhabit humid and subtropical forests of South America, especially the Brazilian Atlantic Forest, the Andean forests of Bolivia and Argentina, and Cerrado zones. Their stems are variable: flat and leaf-like (L. houlletianum), cross-shaped angled (L. cruciforme), or cylindrical (L. lumbricoides), always jointed and functionally spineless. Flowers are small, tubular, and often fragrant, followed by ornamental berries in white, pink, violet, or black tones. Some authors include Lepismium within a broad Rhipsalis.
Leptocereus
Leptocereus
Leptocereus is a genus of columnar cacti from the Caribbean, endemic to the Greater Antilles: Cuba, Hispaniola (Haiti and the Dominican Republic), and Puerto Rico, with some species also in Jamaica and the Virgin Islands. They are shrubby to arborescent cacti with slender stems, generally few pronounced ribs, rigid spines, and nocturnal tubular flowers in white to pink tones. The genus represents an independent insular adaptive radiation within Caribbean Cactaceae, and many of its species face extinction threats due to habitat destruction, deforestation, and grazing in Caribbean dry ecosystems and thorn scrub. Taxonomically complex: some species have been treated as Consolea, Dendrocereus, or Neoabbottia.
Leuchtenbergia
Leuchtenbergia
Leuchtenbergia is a monotypic genus of Cactaceae containing only L. principis, commonly known as the "agave cactus" or "false agave." It is one of the most morphologically unusual cacti: it produces long triangular tubercles 10–12 cm long resembling agave leaves, topped by apical areoles bearing long papery spines up to 15 cm long with a paper-like texture. The species is native to the semi-arid plateau of central and northern Mexico (Coahuila, Durango, Zacatecas, San Luis Potosí, Guanajuato, Querétaro), where it grows in grasslands and xerophilous scrub on limestone or calcareous-clay soils. Its bright yellow flowers emerge from the terminal areoles of the youngest tubercles and have a cedar-wood fragrance. The genus was named by W.J. Hooker in honor of Duke Eugen of Leuchtenberg (1817–1852). It is the only cactus that produces papery spines in adults, a unique character in the entire family. Phylogenetically it is closely related to Ferocactus within tribe Cacteae.
Leuenbergeria
Leuenbergeria
Genus of primitive leafy cacti in the family Cactaceae (subfamily Leuenbergerioideae), segregated from genus Pereskia by Lodé in 2012. They are among the most phylogenetically basal cacti: they have true persistent leaves — unlike most cacti which have reduced or absent leaves — and thus represent an evolutionary stage close to the ancestor of modern cacti. Native to the Caribbean (Greater Antilles) and northern South America. Their flowers are large with coloured petals, and they produce edible fleshy fruits.
Lophophora
Lophophora
Lophophora is a small genus of spineless cacti from northern and central Mexico and southern Texas, world-famous for containing psychoactive alkaloids, primarily mescaline in L. williamsii (peyote). They are globose to flattened, extremely slow-growing cacti with a soft grayish-green to yellowish body, poorly defined ribs, and areoles bearing tufts of white or cream hairs instead of spines. Flowers are small, pink or white, emerging from the apex. The taproot can be several times longer than the visible body. Peyote (L. williamsii) holds millennia-old spiritual and ceremonial importance for the Wixáritari (Huichol), Tepehuan, Navajo, Comanche, and the Native American Church of the United States. It is one of the most important plants in the history of ethnobotany and anthropology. All members of the genus are protected under CITES Appendix II. Cultivation and trade are regulated or prohibited in most countries, though indigenous ceremonial use enjoys legal protection in Mexico and the USA.
Maihuenia
Maihuenia
Maihuenia is a small genus of cacti in the subfamily Maihuenioideae, considered one of the most primitive within Cactaceae along with Pereskia. Its two species form creeping cushions or dense pads of short cylindrical stems bearing small persistent leaves (unlike most cacti), long spines, and solitary yellow flowers. They are endemic to the arid and semi-arid regions of the Andes and Patagonia of Chile and Argentina, where they endure extreme conditions: intense frosts to -20 °C, hurricane-force winds, winter snow, and poor volcanic rock or gravel soils. They are among the few Cactaceae tolerant of prolonged freezing temperatures. Phylogenetically, Maihuenia retains ancestral characters of Cactaceae: its persistent rudimentary leaves and flower and fruit structure reveal the evolutionary "missing link" between normal-leaved plants and leafless succulent cacti. The genus was described by F.A.C. Weber in 1898.
Maihueniopsis
Maihueniopsis
Maihueniopsis is a genus in the subfamily Opuntioideae comprising around 30 species of cushion-forming, creeping, or shrubby cacti distributed mainly in the Andes and arid zones of southern South America: Chile, Argentina, Bolivia, and Peru. They are related to Opuntia but distinguished by their short cylindrical to globose stems, strong spines, and adaptation to extreme altitudes (up to 5 000 m) and cold, xeric climates. Many species form dense pads covering large expanses of arid Andean and Patagonian terrain. They are tough cacti highly resistant to drought, snow, and frost. The genus was segregated from Opuntia by Ritter and later circumscribed by R. Kiesling. Notable is Maihueniopsis darwinii, collected by Charles Darwin during the voyage of HMS Beagle in 1833 in Patagonia, making it one of the first South American cacti studied by Western science. Several species are of great interest for alpine gardens and Andean cactus collections.
Mammillaria
Mammillaria
Mammillaria is the largest genus in Cactaceae with more than 200 accepted species, distributed primarily in Mexico (where the vast majority of species occur) and secondarily in the southern United States, the Caribbean, and northern South America. They are distinguished from all other genera by their tuberculate (not ribbed) structure: tubercles are cone-cylindrical protuberances bearing apical areoles, while flowers and fruits emerge from axillary woolly or bristle-bearing zones between tubercles — a diagnostic character unique to this genus. Most species form globose to cylindrical plants, solitary or densely caespitose, of small size (5–20 cm), although some reach 40–50 cm. Flowers are typically small (1–3 cm) and form striking crowns or rings at the top of the plant; the floral palette encompasses pink, red, white, yellow, and purple. Fruits are elongated bright-red to pink or green berries that persist long on the plant. Numerous species exude milky latex when cut (section Hydrochylus). The genus was described by Haworth in 1812; the current classification (D.R. Hunt, CITES Cactaceae Checklist) recognizes more than 200 valid species.
Matucana
Matucana
Genus of globose to cylindrical cacti from the Peruvian Andes, famous for their large zygomorphic tubular flowers in shades of orange, red, magenta, and yellow. Contains ~20-35 species endemic to Peru, distributed from the western slopes to the interandean valleys, at altitudes of 500–3,500 m. Many species are difficult to access and protected by CITES Appendix II.
Melocactus
Melocactus
Genus of globose cacti characterized by the development of a CEPHALIUM — a specialized woolly and bristly structure that grows at the apex of mature plants (after 5–15 years) from which flowers and fruits emerge. It is the most diagnostic feature of the genus and one of the most fascinating in the entire Cactaceae family. Contains ~35–40 species distributed in the Caribbean, coasts of Central and South America (Colombia, Venezuela, NE Brazil, Peru, Bolivia). Name derived from Latin melo (melon) + cactus, for the shape of its fruits. Historically the first cactus described by Linnaeus (1753, as Cactus melocactus).
Micranthocereus
Micranthocereus
Columnar cacti endemic to Brazil, concentrated in the campos rupestres and caatinga of Bahia and Minas Gerais. They produce very small flowers (1–2 cm) in cephalium-like lateral zones along the stem — a diagnostic character of the genus. Several species produce pseudocephalia. Notably M. purpureus, one of the very rare cacti with truly purple-violet flowers.
Micropuntia
Micropuntia
Genus of small opuntioid cacti of the Great Basin of North America. Characterized by miniaturized stems, tiny pads, prominent glochids, and small flowers. Endemic to cold sand and gravel deserts. Separated from Opuntia by the small size of all its organs.
Mila
Mila
Monotypic genus of Cactaceae, endemic to the arid Andean slopes of Peru. Characterized by low columnar stems, dense spinescence, and small yellowish-white flowers emerging near the apex. The name is an anagram of Lima, capital of Peru, where the genus was originally collected.
Miqueliopuntia
Miqueliopuntia
Monotypic genus of Cactaceae, tribe Opuntieae, endemic to the arid coast of Chile. Characterized by flattened pads, acicular spines, and yellow flowers. Named in honor of Dutch botanist Friedrich Anton Wilhelm Miquel (1811–1871). Separated from Opuntia by morphological and molecular characters.
Mirabella
Mirabella
Genus of columnar cacti endemic to the campos rupestres and cerrado of Minas Gerais, Brazil. Slender columnar stems, erect or arching, with well-defined ribs. White nocturnal flowers, bat-pollinated. Closely related to Cereus and Monvillea, separated by floral and molecular characters. Endemic to rocky outcrops of Minas Gerais state.
Monvillea
Monvillea
Genus of columnar cacti of southern South America, mainly of the Southern Cone and Plata basin (Argentina, Paraguay, Bolivia, Brazil, Peru, Chile). Thin climbing, semi-climbing or prostrate stems, frequently with mottled dark green and gray-white epidermis. White or pink nocturnal flowers, large (10–20 cm). Named in honor of Louis François Marie Monville (1776–1858), French amateur botanist and cactus collector. Some modern authors synonymize it with Cereus; maintained here for its traditional and morphological recognition.
Morangaya
Morangaya
Monotypic genus of Cactaceae endemic to Baja California, Mexico and Cedros Island. Characterized by thin hanging or climbing stems (saxicolous epiphyte), tufted spines, and red diurnal flowers. Known as the "hanging cactus of Baja California". Segregated from Echinocereus by Rowley in 1974 based on the hanging habit and hummingbird pollination.
Myrtillocactus
Myrtillocactus
Genus of columnar cacti from Mexico and Guatemala, family Cactaceae. Characterized by arboreal or shrubby blue-green columnar stems, closely spaced areoles, small white or cream flowers in clusters of 5–9 per areole, and tiny blue-black clustered fruits (resembling blueberries or bilberries — hence the name: "Myrtillus" = bilberry + "cereus" = columnar cactus). The fruits, called "garambullos" in Mexico, are edible and widely marketed. Key in pollination and seed dispersal in Mexican xerophytic scrublands.
Neobuxbaumia
Neobuxbaumia
Genus of giant columnar cacti endemic to Mexico, mainly the states of Oaxaca, Puebla, Guerrero, Tamaulipas, and Veracruz. Imposing erect columnar stems up to 15 m tall, with numerous ribs (up to 50+ in N. polylopha). Some species develop voluminous lateral cephalia. White or pink nocturnal flowers. Fleshy fruits. Pollinated by bats and hawk moths. The name combines "Neo" (new) + "Buxbaumia" (in honor of Franz Buxbaum, prominent 20th-century Austro-Hungarian cactologist). Iconic elements of the Tehuacán-Cuicatlán Valley landscape (UNESCO Biosphere Reserve), the region of maximum cactus richness on the planet.
Neoraimondia
Neoraimondia
Genus of giant columnar cacti endemic to Peru and extreme northern Chile. Characterized by branched columnar stems up to 8 m and, above all, by MULTI-SPINED AREOLES: each old areole produces successive new areoles, forming a very long spine cluster (up to 20–30 cm) that persists for years — a unique structure in Cactaceae. Small pink diurnal flowers. Named in honor of Antonio Raimondi (1826–1890), Italian-Peruvian naturalist and geographer who produced the first modern atlas of Peru. The prefix "Neo" (new) distinguishes this genus from the earlier homonym. Iconic element of the Peruvian coastal desert landscape.
Neowerdermannia
Neowerdermannia
Genus of geophytic globose cacti of the Andes of Bolivia, Peru, Chile, and Argentina. Extremely adapted to high-altitude Andean punas and quebradas: the main body remains BURIED in the soil (geophytic), with only the spiny crown emerging. This strategy protects against intense frost, wind, and herbivory. Roots are napiform and tuberous, accumulating reserves. Pink-violet showy flowers that emerge directly from the ground. Named in honor of Erich Werdermann (1892–1959), prominent German botanist specializing in South American cacti.
Obregonia
Obregonia
Monotypic genus of Cactaceae, one of the most singular in the entire family. Flattened globose body with LARGE, TRIANGULAR AND FLATTENED TUBERCLES arranged in a spiral, identical to artichoke leaves (hence its common name "artichoke cactus"). Exclusively endemic to the Jaumave Valley, Tamaulipas, Mexico. CITES Appendix I (maximum protection). NOM-059 Mexico: endangered. Named in honor of Álvaro Obregón (1880–1928), revolutionary general and president of Mexico. The species denegrii was described by Alberto Vojtěch Frič in 1925 and dedicated to Alberto Denegri, Tamaulipas cultural promoter. One of the most sought-after cacti by specialist collectors.
Opuntia
Opuntia
Genus of cacti in subfamily Opuntioideae, commonly known as prickly pears, nopal or paddle cacti. With over 200 accepted species it is one of the largest genera in Cactaceae. Their flattened stem segments (cladodes) are covered in glochids — microscopic barbed spines that detach on contact. Distributed primarily in the Americas, they have been widely naturalised in Mediterranean regions, Africa, Australia and Asia. Several species have great economic importance as producers of prickly pear fruit, edible pads (nopalitos) and as host plants for Dactylopius coccus, from which cochineal dye is extracted.
Opuntia
Opuntia
THE TYPE GENUS OF THE CACTACEAE FAMILY. The classic "nopal" or "prickly pear" — one of the most important plant genera in the Americas, with more than 200 species distributed from Canada to Patagonia. Characterized by CLADODES (flattened pads), GLOCHIDS (tiny hooked spines in tufts that embed in skin), variable true spines, yellow to red flowers, and fleshy fruits (prickly pears/tunas). Of exceptional agricultural, gastronomic, and cultural importance in Mexico: the pads (nopales) and fruits (tunas) are staple foods commercially traded worldwide. Also fundamental in cochineal dye production (Dactylopius coccus) on O. cochenillifera and relatives. The name "Opuntia" derives from the ancient region of Opus, Greece, where Pliny the Elder described a spiny plant (though not the same as the American cactus).
Oreocereus
Oreocereus
Genus of Andean columnar cacti, known as "old men of the mountain" or "woolly Andean cacti". Characterized by columnar stems covered with DENSE WHITE OR COLORED WOOL and long bristles, giving them the appearance of being covered in hair or snow. Red or pink tubular diurnal flowers, hummingbird-pollinated. Endemic to the Andes of Peru, Bolivia, Chile, and Argentina, at altitudes of 3000–4500 m. The name combines "oreo" (from oros = mountain in Greek) + "cereus" (columnar). The wool acts as thermal insulation and protection against high-altitude UV radiation. Very popular in cactus collections for their striking woolly appearance.
Oroya
Oroya
Genus of globose to shortly cylindrical cacti, endemic to the Peruvian Andes. Plants grow semi-buried in the soil in puna and high Andean grasslands at 3000–5000 m. Distinguished by pectinate spines arranged in perfect stars and diurnal flowers in yellow-cream to pink tones. Small genus with 5–6 accepted species.
Ortegocactus
Ortegocactus
Monotypic genus of cacti from Oaxaca, Mexico. Small gray globose plants with grayish spines forming stars. The single species, O. macdougallii, is endemic to dry valleys of Oaxaca. Originally placed in Mammillaria; currently recognized as an independent genus for unique spine and tubercle characteristics.
Pachycereus
Pachycereus
Genus of giant columnar cacti of Mexico and Baja California. Includes some of the most imposing plants of the American continent: Pachycereus pringlei reaches up to 20 m and can live 300 years. They form cactus forests (cardonales) that are key ecosystems in Baja California and the Mexican Pacific. Many species are emblematic of Mexican culture.
Parodia
Parodia
Very large genus including the former genera Notocactus, Eriocactus and Wigginsia. One of the most diverse and cultivated cactus genera in the world, with over 100 species ranging from small globes to columns. Native to temperate South America (Argentina, Brazil, Uruguay, Bolivia, Paraguay). Brightly colored flowers: yellow, red, orange, pink, violet. Many species are popular ornamentals.
Pediocactus
Pediocactus
Genus of small globose cacti of western North America, especially adapted to extreme environments of the Great Basin and Colorado Plateau deserts. Many species are protected (CITES I or federal) for their extremely restricted ranges. The genus includes some of the most threatened plants of the North American continent.
Pelecyphora
Pelecyphora
Small Mexican globose cacti with hatchet-shaped tubercles (pelekys = Greek for hatchet). Endemic to San Luis Potosí and Tamaulipas. The crustacean-like pectinate areoles distinguish P. aselliformis. P. strobiliformis has imbricate scales like a pinecone. CITES Appendix II.