The Succulent Plant Page goes to Families of Succulent Plants goes to

The Cactus Page


Search this site:        
Botanical BookmarksBotanical Glossary SITEMAP Email: webmaster

Cactaceae   -   Cactus Family
Greek: kaktos = a prickly plant (Spanish artichoke) from Sicily. Linnaeus (1737)


The large family Cactaceae is one of the most distinctive familes of dicotyledenous flowering succulent plants, with around 90 genera and 2500 species, ranging in size from less than half an inch to tens of feet in height and exlusively native to the American continent including the West Indies. The solitary exception to this New World distribution is that of the epiphyte Rhipsalis baccifera which is distributed in Africa, Madagascar and Ceylon as well as in South America, Mesoamerica and the Carribean. Most species of Cactaceae are spiny stem succulents, although there are a few woody shrubs (Pereskia) and more or less succulent epiphytes. This family contains numerous genera which seem to be constantly under revision.
The Cactaceae are distinguished by modified buds that have evolved into specialised areoles from which grow multiple spines and glochids (top right). These should be distinguished from solitary spines or thorns on other plants e.g. spiny Euphorbias, that sometimes branch above the plant body. In some cactus species spination is minimal, or occurs only during some phases of the succulent plant's life or vestigal spines are present as hairs. Leaves where present are alternate, but usually reduced or absent. Fruits are generally berries with multiple seeds, which may be surrounded by juicy flesh or by a more or less dry membrane and may have external spines.
Betalain pigments are present and characteristic of the family Cactaceae and of the Order Caryophyllales in which they are included, as is absence of anthocyanin pigments found in other families of flowering plants. Betalains and anthocyanins never occur in the same plant. Betalains are responsible for the red or violet colouration of some cacti when stressed. Ferulic acid in the cell walls of Cactaceae is also a common characteristic.

Hylocereus megalanthus - Yellow Pitahaya

Several species of cacti are cultivated for their juicy fruit (e.g. Opuntia ficus-indica, Selenicereus sp., Hylocereus sp.). Through introduction, Cactaceae and especially Opuntia are found throughout the tropics. In some places cacti have become invasive weeds.
Many species of cacti are cultivated as ornamental house plants or for dry landscaping and they are grown from seed in vast numbers. Some species e.g. Echinocactus grusonii are far more common in cultivation than in their habitat, much of which was destroyed by construction of a reservoir. All species of cacti are protected as CITES 1 or CITES 2 plants, which presents a barrier to free trade even for nursery grown cacti and artificial hybrids with no natural distribution.
Cactus taxonomy appears to follow a record of their assumed evolutionary history. Various authors have estimated that the Cactaceae evolved as recently as in the last 10,000 years or as long ago as 20 - 30 million years. However, as cacti are not well-represented in the fossil record, the logical taxonomic sequence is based mainly on morphology. Recent DNA studies support the general groupings, but suggest some taxonomic rearrangements of species. Cacti generally have 22 chromosomes.

spine cluster
spine cluster
spine cluster
Examples of
cactus spine clusters

Summary of Cactaceae


Cacti Succulent Plants Dry Gardening Webmaster's Choice
icon icon

go to top  Subfamily Pereskioideae   (leafy cacti)
The 20 species of succulent plants in this subfamily are shrubs and trees with persistent flat leaves, areoles with spine clusters and no glochids. These plants are thought to be low down in the evolutionary tree of the Cactaceae. The two mat-forming species in Maihuenia with persistent rounded succulent leaves are sometimes separated into Subfamily Maihuenioideae.
All species in this subfamily are native to central and South America.

Maihuenia  (Philippi ex F.A.C.Weber) K. Schumann 1898
Name: Latinised form of maihuén, Chilean common name for these cacti 
The genus Maihuenia includes two species of dwarf mat-forming cacti as the only members of Subfamily Maihuenioideae. These succulent plants consist of short segmented cylindrical stems with small persistent rounded succulent leaves and typically 3 white spines per areole. Flowers in shades of yellow are produced near the ends of the stems and are followed by club-shaped fruits.
Native to elevations from sea level to up to 8000 ft in the Andes Montains of Argentina and Chile. Maihuenia experience frost in their habitat and tend to be cold-wet hardy in cultivation, especially M. poeppigii.

Maihuenia patagonica - RBG Kew

Maihuenia patagonica  (Philippi) Britton & Rose 1919
Name: = of Patagonia, native region 

Photographed in the Alpine House at RBG Kew. Said to be the least hardy of the two species, so needs to be kept under cover.

Maihuenia poeppigii - RBG Kew

Maihuenia poeppigii  (Otto ex Pfeiffer) F.A.C. Weber 1898
Named for: Eduard Pöppig, 19th century German naturalist and explorer 

Photographed growing outdoors at RBG Kew. This is the most hardy of the two species and is the only cactus that consistently survives the English Winter outside in my own garden, potted up in almost pure granite chippings to ensure free drainage.

Pereskia  Miller 1754
Named for: Nicolas-Claude Fabri de Peiresc, 16th century French astronomer, antiquarian & savant 
The genus Pereskia includes 17 species of tropical woody shrubs, climbers or tree-like cacti with thin stems and substantial, persistent non-succulent green leaves. A characteristic feature in common with other cacti are the clusters of spines originating from areoles. Roots may be thickened or even tuberous. Flowers are single and resemble those of a wild rose. It is thought that the primitive features of the genus Pereskia resemble those of a common ancestor to all cacti.
Native to a range from Brazil to Mexico including the West Indies. Pereskia is often used to make thorny hedges. Pereskia aculeata has edible fruit (Barbados gooseberry) but may be considered invasive in some places.

Pereskia grandifolia - RBG Kew
Pereskia weberiana - RBG Kew

Pereskia grandifolia  Haworth 1821 (Rose Cactus) Syn. Pereskia grandiflora Hort. ex Pfeiffer 1837
Name: Latin grandis = large + folius = leaves or + florus = flowers 
This cactus grows as a non-succulent tree or woody shrub with a grey-brown trunk up to 10 ft tall. The woody, branching stems have areoles bearing clusters of spines and brownish tomentum but also ovate, glossy, deciduous leaves on short petioles. Flowers resembling those of wild roses in shades of pink are freely produced at the stem ends.
Native to dry tropical forests of North-Eastern Brazil. Pereskia grandiflora is grown for its showy flowers and also features in traditional medicine to reduce swelling and inflammation and as an anti-cancer remedy.
Photographed at RBG Kew.
Pereskia weberiana  K. Schumann 1898
Named for: Frédéric Albert Constantin Weber (1830 - 1903), French botanist 
A shrubby non-succulent cactus with areoles bearing both spine clusters and glossy ovate leaves.
Native to dry forests of the Andean valleys in Bolivia, at altitudes up to 6000 ft.
Photographed at RBG Kew.

go to top  Subfamily Opuntioideae
This sub-family includes over 300 species of cacti with the common characteristic of irritating barbed hairs (glochids) as well as ordinary spines. The seeds are hardened with a stone-like aril. Leaves where present are vestigial and short lived. Members of this subfamily range in size from mat-forming plants to shrubs and trees.
Native to a very wide range from central Canada to Patagonia in South America and naturalised in many warm climates where they may be regarded as invasive.

Cylindropuntia  (Engelmann) Knuth 1754 (Cholla)
Name: = cylindrical Opuntia referring to the stems 
The 35 species of cacti in Cylindropuntia were formerly included in Opuntia but were separated on the basis of cylindrical stem segents and papery sheaths on their barbed spines. Cylindropuntia species range from small sub-shrubs to large trees.
Chollas are native to the South-Western USA, Northern Mexico and the West Indies. Large stands of genetically homogenous chollas occur in some places, where plants propagate vegetatively from dehiscent stem segments.

Cylindropuntia bigelovii

Cylindropuntia bigelovii  (Engelmann) F.M. Knuth 1935 (Teddy Bear Cholla, Jumping Cholla)
Syn. Opuntia bigelovii  Engelmann 1856
Named for: John Milton Bigelow (1804 - 1878) American surgeon & botanist 

Photo: A forest of Cylindropuntia bigelovii. Cactus garden, Joshua Tree Park, California.

Opuntia  (Linnaeus) P. Miller 1754 (Prickly Pear, Nopales [pads], Tuna [fruit])
Named for: Opus "a town of Locris in Greece". Theophrastus (371-287 BC) mentioned an edible plant growing there that was propagated by leaf cuttings. However, this could not have been an Opuntia as the genus originates from the Americas, unknown in that era. 
The genus Opuntia is a large group of cacti with flattened paddle-shaped stem segments (cladodes) furnished with two sorts of spines: large fixed spines and small, hairlike spines (glochids) that easily detach from the plant and penetrate the skin causing irritation.
Native to a wide range of the Americas from British Columbia and Canada to Patagonia, South America, the West Indies and the Galapagos Islands. Opuntias have been introduced to many countries with mild climates and are considered invasive in some.

Opuntia basilaris - Death Valley California.

Opuntia basilaris  Engelmann & J.M. Bigelow, 1857 (Beavertail Cactus)
Photo: Death Valley California.

Opuntia dactylifera - Holly Gate Cactus Nursery reference collection

Opuntia dactylifera  Vaupel 1913
Syn. Maihueniopsis bolivianum  (Salm-Dyck) R. Kiesling 1984

Photo: Holly Gate Cactus Nursery reference collection

Opuntia erinacea var. hystricina

Opuntia erinacea var. hystricina  (Engelmann & J.M. Bigelow) L.D. Benson 1940

Photo: near Salt Flats, Texas.

Opuntia engelmannii

Opuntia engelmannii  Salm-Dyck ex Engelmann 1850

Photo: near Marathon, Texas.

Opuntia microdasys

Opuntia microdasys  (Lehmann) Pfeiffer 1837 (Bunny Ears Cactus)
Name: Greek mikros = small + dasus = hairy 
This shrubby cactus grows up to 2 ft tall with stems formed from flattened pads joined end to end. The pads have dense tufts of white or yellow glochids but no spines. These glochids are barbed and detatch into one's skin with the slightest touch, causing irritation until removed. Flowers are yellow.
Native to central and Northern Mexico. Despite the irritating glochids, this species is common in cultivation and there are numerous selected forms.
Opuntia rufida from Northen Mexico into Texas, is very similar but has rusty-brown glochids.

Opuntia sp.

Opuntia sp.

Labelled as O. microsphaericus but that doesn't seem to be a valid name.
Might be a Tunilla sp.
Photo: Holly Gate Cactus Nursery reference collection.

Tephrocactus sp.

Tephrocactus sp.

Photo: Holly Gate Cactus Nursery reference collection

go to top  Subfamily: Cactoideae
This is the largest and most diverse subfamily within the Cactaceae, including over a thousand species. This group of plants covers a wide range of forms and lifestyles, ranging in size from less than half an inch to trees over 60ft tall. Most but not all cacti have spines but glochids are never present and leaves are absent or vestigial e.g. cotyledons. Instead of leaves, stems are photosynthetic. Most flower colours are seen with the exception of blue. Flowers are followed by berries which may be fleshy or dry and contain multiple small seeds.
All species of cacti are native to the Americas with the exception of a single species (Rhipsalis baccifera) which is also found in India, Ceylon and Africa.

Ariocarpus fissuratus

Ariocarpus  Scheidweiler 1838 (Living Rocks)
Name: Greek aria = an oak type and carpos = fruit 
The genus Ariocarpus includes 8 species of cacti whose spines have mostly degenerated into tufts of wool. These plants grow flush with the ground and have thick tap roots which require very well-drained conditions. The plant consists of a rosette of spineless, triangular tubercles and in mature plants a wooly apex. The succulent tubercles are protected from herbivores by their content of bitter alkaloids e.g. Hordenine.
Native to limestone mountains of South Texas into central Mexico. The single species in Texas (A. fissuratus) is not uncommon within its range, but well camoflagued among rocks. However, the shocking pink flowers produced in the Autumn betray the positions and numbers of plants. In cultivation Ariocarpus are very slow growing and require careful watering or the tap root will rot. Some people like to add ground limestone to their potting mixture, which must be very free-draining. Grafting is commonly used to increase the growth rate, but produces bloated plants.

Ariocarpus fissuratus Ariocarpus fissuratus

Ariocarpus fissuratus  (Engelmann) K. K. Schumann 1894 (Living Rock Cactus)

Native to Northern Mexico and Texas.
Photo: Big Bend National Park, Texas.

Ariocarpus retusus

Ariocarpus retusus  Scheidweiler 1838
Name: Latin retusus = blunt tip 
This somewhat variable plant is the type species for the genus. The rosette of spineless tubercles is supported by a subterranean tuberous body which requires excellent drainage.
Native to the high Chihuahuan desert in the Mexican states of Coahuila, Nuevo León, San Luis Potosi, Tamaulipas, and Zacatecas, growing on limestone and gypsum.

Ariocarpus scapharostrus

Ariocarpus scaphirostris  F. Boedeker 1930
Syn. Ariocarpus scapharostrus  Boedecker 1930
Name: Latin scaphe = peak + rostrum = face 
The tubercles of the mature plant are spineless, but seedlings have spines.
Native to the Mexican state of state of Nuevo León.

go to top  Astrophytum   Lemaire 1839
Name: Greek astron = star + phyton = plant 
Astrophytum is a small genus of six species of North American cacti, within which is a remarkable diversity of form. The cactus bodies are globular to short columns with or without spines. The body plan of Astrophytum is star-shaped with 5 - 8 ribs, which may be deeply incised or minimally delineated by a line of areoles. The recently-discovered, distinctive A. caput-medusae has sprawling stems arising from a caudex and is sometimes regarded as a member of the monotypic genus Digitostigma. The surface of all species generally has white patches of flocking but this may be absent or washed away by rain.
Astrophytum are native to Southern Texas and Mexico.
The variable symmetry of form and white markings of these plants has appealed to collectors, especially in Japan where many extreme examples have been bred.

Astrophytum myriostigma

Astrophytum myriostigma  Lemaire 1839 (Turk's Head Cactus)
Name: Greek myrios = innumerable + stigma = stain (many-dotted) 
The three to seven, usually five-ribbed solitary plant body is covered with thousands of tiny dots of white trichomes to a variable extent. There are no spines. Yellowish, sweetly-scented flowers with many petals are produced at the apex of the plant and are followed by a large (1 inch) red fruit.
Native to the Mexican states of Coahuila, Durango, Nuevo Leon, San Luis Potosi and Tamaulipas. The plant should be watered from below to preserve the white flocking. Some all-green horticultural selections have no trichomes.
Photo: Benno Stander 2014, of a cultivated plant in South Africa.

Astrophytum myriostigma quadricostatum

Astrophytum myriostigma quadricostatum  M. Mittler 1841
A nursery-selected form with four ribs instead of the more usual five ribs. Such plants also occur in the wild population. Flowers are pale yellow. Further selections have led to all-green plants without white trichomes and several named cultivars with distinctive patterns of white trichomes.

Astrophytum ornatum

Astrophytum ornatum  (De Candolle) Weber ex Britton & Rose 1922 (Bishop's Cap)
Name: Latin ornatus = decorated, referring to the woolly flakes on the body 
This is the largest species of Astrophytum. The five to ten, usually eight-ribbed solitary plant body has bands of white flocking, to a very variable extent, in some variants becoming near confluent. Yellowish flowers with many petals are produced at the apex of the plant.
Native to canyons and limestone cliffs in the Mexican states of Hidalgo, Queretaro and Guanajuato.

go to top  Blossfeldia  Werdermann 1937
Named for: Harry Blossfeld (1913 - 1986) German botanist living in Brazil. 
Blossfeldia is a genus of cacti with very small button-like bodies without ribs, tubercles or spines. Blossfeldia is probably monotypic for Blossfeldia liliputana, but several species have been described.
Native to the Eastern side of the Andes mountains of Bolivia and Argentina at elevations of 4,000 to 12,000 ft.
Blossfeldia is sometimes included in Parodia as Parodia liliputana (Werdermann) N.P. Taylor 1987.

Blossfeldia liliputana

Blossfeldia liliputana  Werdermann 1937
Named for: fictional country of Lilliput inhabited by a race of tiny people (Gulliver's Travels, 1726, Jonathan Swift) 
The tiny plant body less than half an inch in diameter has no rib, tubercles or spines but is dotted with areoles bearing white hairs. Unlike most other cacti, Blossfeldia liliputana has no thickened outer cuticle but instead appears to be poikilohydric (can withstand dessication). The small flowers are white or pale yellow with bright yellow stamens.
Native to a range from Southern Bolivia to North-Western Argentina, growing in rock crevices on cliffs. Grafting accelerates growth but produces unnatural bloated golf ball sized plants.

go to top  Cleistocactus  Lemaire
Name: Greek kleistos = closed, referring to the flowers that seldom open 
The genus Cleistocactus includes 50 or more species of South American columnar cacti whose tall, narrow ribbed stems have closely spaces areoles with many flexible spines giving some species a furry appearance. Stems usually branch at their base making large shrubby clumps. Their red or orange tubular flowers have exserted style and stamens but often hardly open otherwise. They tend to be produced on the sunny side of the stem.
Native to the mountains of Argentina, Bolivia, Peru, and Uruguay, growing at elevations of up to 9800 ft. Several other genera have been lumped into Cleistocactus, making the genus more diverse. Plants that used to be in the genus Borzicactus have flowers that open a little wider than those of the original Cleistocactus.

Cleistocactus candelilla

Cleistocactus candelilla  Cárdenas 1952
Name: Spanish candelilla = small candle  
Tubular pink-red flowers form mostly on the sunny side of the stem and are followed by pink fruits.
Native to the Bolivian regions of Cochabamba, Potosí and Santa Cruz and especially Amboró National Park.

go to top  Copiapoa  Britton & Rose 1922
Named for: the town of Copiapó in Northern Chile. 
There are around 26 species of Copiapoa. Bodies are speroidal to columnar with ribs and a wooly apex from which yellow funnel-shaped flowers arise. Spination varies between species from strong to nearly absent and roots may be fibrous or tuberous.
Native to the dry coastal margin of Northern Chile, especially the Atacama desert. Rain is very infrequent but coastal fogs provide some moisture. In habitat, growth of some species is extremely slow and not much better in cultivation once past the seedling stage. Grafting speeds up growth but leads to bloated plants. Habitat plants of many species have a white bloom of waxes that protects them from ultraviolet and reduces loss of moisture, but plants grown under glass experiencing less ultraviolet may not develop this coating.

Copiapoa barquitensis

Copiapoa barquitensis  F. Ritter (1960) (nom. inval.)
Named for: Barquito = coastal town and port in Chile 
Copiapoa hypogaea  F. Ritter 1960, Copiapoa hypogaea var. barquitensis  F. Ritter 1980
Name: Greek hypogaea = underground, referring to the sunken nature of the plant body. 
This cactus forms clumps of brown to gray-green, tuberculate bodies with wooly tubercles bearing one or more short spines, often absent on older parts of the plant.
Native to the Atacama desert of Chile.
Photo: Holly Gate Cactus Nursery reference collection

Coryphantha - RBG Kew

Coryphantha (Engelmann) Lemaire 1868 (Beehive Cactus)
Name: Greek koryphe = crown + anthos = flower 
The 57 species of cacti in the genus Coryphantha have globose bodies whose tubercles have a distinctive longitudinal groove on their upper surface. The spine cluser may have a central spine but this is a variable feature. Flowers in pink or yellow form at the growing apex of the plant followed by seeds with a reticulate (net-like) surface.
Members of this genus are widely distributed from the US state of Montana across the Southern states into Mexico and central America.

Coryphantha calipensis - RBG Kew

Coryphantha calipensis  H. Bravo Hollis 1992
Name: refers to the small town of Calipan in the Mexican State of Puebla 
Flowers are yellow.
Photographed at RBG Kew.

go to top  Echinocactus  Link & Otto 1827
Name: Greek echinos = spiny + cactus 
One of two genera of classic barrel cactus with 6 species. Plant bodies have deep ribs with heavy spination and relatively small flowers. The ovaries and fruits are distinctively woolly although the flower tube is scaly.
The best known member of the genus is the Mexican Echinocactus grusonii (Golden Barrel). Through habitat destruction, the wild plant has become rare and endangered. However, it is exceeding common in the hortultural trade and propagated from seed in very large numbers.

Echinocactus grusonii
Echinocactus grusonii seedlings
Above: E. grusonii seedlings

Echinocactus grusonii  H. Hildmann 1886 (Mother in Law's Cushion, Golden Barrel Cactus)
Named for: Hermann August Jacques Gruson (1821 - 1895) German engineer & cactus collector 
The spherical green plant body of a mature plant has up to 35 prominent ribs edged with golden-yellow spines. Young plants have somewhat tuberculate ribs. With age, the body may become 4 ft in height and more cylindrical. Mature plants can offset to form a small clump. As with other barrel cacti, the body tends to lean to the south or southwest so that the spines can better filter the fierce sunlight. Yellowish hairs produced from the areoles form a wooly mat around the top of a mature plant.
A ring of small (for the size of the plant) yellow flowers are produced around the crown of the plant in late Spring or early Summer and are followed by small yellowish fruits terminated by the dried flowers. Fruits are full of small brown seeds from which it is easy to grown new plants. Seedlings are initially bi-lobed.
Echinocactus grusonii is native to the Mexican states of Querétaro and Zacatecas. Much of the population was lost when the Zimapán Dam and reservoir was built in Hidalgo although conservationists rescued many of the plants. Selected cultivars are known with white spines or without spines.
Echinocactus grusonii is a popular feature plant for dry landscaping in warm climates.

Echinocactus horizonthalonius - Maverick Mountain, Texas

Echinocactus horizonthalonius  Lemaire 1839
Always solitary. Flowers are pale pink to magenta in late Spring to early Summer. The spiny cage surrounding the plant body often persists after death of the plant and can sometimes be found rolling around in the wind.
Native to the Chihuahuan Desert from Arizona, New Mexico, Texas and into North-Eastern Mexico. Delightful plants in their habitat but very difficult in cultivation.
Left: Echinocactus horizonthalonius, Maverick Mountain, Texas.
Left: This specimen of Echinocactus horizonthalonius had rather short stubby spines compared to the rest of the population.

Echinocactus horizonthalonius - Maverick Mountain, Texas
Echinocactus platyacanthus

Echinocactus platyacanthus  Link & Otto 1827
Syn. Echinocactus ingens  Zuccarini ex Pfeiffer 1837
Name: Greek platyacanthus = with wide thorns 
This barrel cactus eventually grows larger than any other, up to 8 ft tall and 5ft wide.
Widely-distributed across North-East and Central Mexico.

Echinocactus polycephalus - Death Valley California.

Echinocactus polycephalus  Engelmann & J.M. Bigelow 1857
This one of the few barrel cacti that can clump up by offsetting. Large many-headed clumps of this cactus are seen in the hot, dry mountains surrounding Death Valley.
Native to a wide range across the deserts of the USA South-West states of Texas, Arizona, Nevada, California and into Northern Sonora, Mexico.
Photo: Death Valley, California.

go to top  Echinocereus  Engelmann 1848 (Hedgehog Cacti)
Name: Greek echinos = spiny + Latin cereus = candle 
Echinocereus have globular or short columnar bodies with deep ribs, often clumping up by basal offsetting with age. The strong spination, arranged along the apex of the ribs, covers the body and may be quite colourful. The flowers are bright reds, pinks and yellows and quite large in some species.
The monotypic genus Morangaya and some species from Wilcoxia have been transferred into Echinocereus.

Echinocereus berlandieri

Echinocereus berlandieri  (Engelmann) J.N. Haage 1859

Photo: Holly Gate Cactus Nursery reference collection

Echinocereus engelmannii - Holly Gate Cactus Nursery reference collection

Echinocereus engelmannii  (Parry ex Engelmann) Lemaire 1868

Photo: Holly Gate Cactus Nursery reference collection

Echinocereus enneacanthus - Big Bend National Park

Echinocereus enneacanthus  Engelmann 1848

Photo: Big Bend National Park

Echinocereus lauii - cultivated, flower

Echinocereus lauii  G. Frank 1978


Echinocereus x lloydii - N. of Marathon, Texas

Echinocereus roetteri var. lloydii  (Britton & Rose) Backeberg 1960
Syn. Echinocereus x lloydii  Britton & Rose 1922,  Echinocereus x roetteri  (Engelmann) Rümpler 1866
This rare plant is probably a natural hybrid Echinocereus pectinatus var. dasyacanthus x Echinocereus coccineus and as such, individual plants may present a variable appearance.
Photographed: N. of Marathon, Texas.

Morangaya pensilis - Holly Gate Cactus Nursery reference collection

Morangaya  G.D. Rowley 1974
Named for: Dr. Reid Moran and Ed & Betty Gay who provided plants and information about the species. 
The monotypic genus Morangaya has been merged into Echinocereus.

Echinocereus pensilis  (Brandegee) J.A. Purpus 1908
Syn. Morangaya pensilis  (K. Brandegee) G.D. Rowley 1974

Photographed at Holly Gate Cactus Nursery reference collection

Echinocereus stramineus - Dog Canyon, Big Bend National Park

Echinocereus stramineus  (Engelmann) F. Seitz 1870

Photo: Dog Canyon, Big Bend National Park

go to top  Echinopsis  Zuccarini 1837 (Hedgehog Cactus)
Name: Latin echinos = hedgehog or sea urchin + cacti, referring to the often dense spination 
As currently constituted, the genus Echinopsis includes over 128 species of South American cacti with prominment ribs, ranging from small globular plants to tree-like cacti. Flower stems are longer than in Echinocactus and the short-lived relatively large funnel-shaped flowers have wooly, hairy or scaled tubes. Flowers are followed by pulpy fruit which may have a hairy skin.
Native to gravelly soils and rocky hillsides across South America (Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay, Peru, and Uruguay). Many former members of former genera e.g. Lobivia, Mediolobivia, Rebutia, Trichocereus have been lumped into Echinopsis. Inter-specific hybridisation is easy within this group and many free-flowering hybrids have been produced.
Lobivia   Britton & Rose 1922   Lobivia has been merged into Echinopsis.
Name: an anagram of Bolivia 
The genus includes 20 species of small globular plants from the highlands of Bolivia, Peru and Argentina. The bee-pollinated flowers are brightly coloured with relatively short flower tubes.
Trichocereus  (Berger) Riccobono 1909 (Torch Cacti)   Trichocereus has been merged into Echinopsis.
Name: Greek trikhos = hair or bristle + cereus = candle 
Trichocereus is a group of about 30 columnar plants, which may be erect or decumbent with one hanging epiphytic species. Some Trichocereus become very large and tree-like. Flowers are typically white and very large with long flower tubes, opening at night for pollination by bats and moths. Native to Argentina, Bolivia, Chile and Peru. Some species produce toxic psychoactive alkaloids.

Echinopsis aff. strigosa Echinopsis aff. strigosa

Echinopsis aff. strigosa  (Salm-Dyck) Friedrich & G.D.Rowley 1974

Native to Argentina.


Echinopsis huascha (Weber) Friedrich & G.D.Rowley 1974
Flower colours range from yellow to orange and red.
Native to Argentina.

chamaecereus silvestrii

Chamaecereus silvestrii  (Spegazzini) Britton & Rose 1922 (Peanut Cactus)
Syn. Echinopsis chamaecereus   H. Friedrich & Glaetzle 1983
Named for: Filippo Silvestri (1873-1949) Italian entomologist & botanist. 
This mat-forming cactus has many long thin stems, initially erect but later decimbent, with 8 - 10 ribs profusely furnished with clusters of 10 - 15 small, bristly, radial spines. Peanut-sized offsets are produced along the main stems, detaching rather easily to start new plants. Funnel-shaped orange flowers are produced freely in late Spring and sporadically later on.
Native to the Andean mountains of Argentina and moderately frost-hardy when dry. Features in many colourful hybrids with other Echinopsis, especially Lobivia species with the hybrids known as Chamaelobivia. Echinopsis chamaecereus f. aureus is a yellowish chlorophyll-deficient mutant commonly seen grafted.

Mediolobivia eos var. roseiflora - cultivated

Lobivia pygmaea (R. E. Fries) Backeberg 1935
Syn. Mediolobivia eos var. roseiflora  Rausch 1972   Rebutia pygmaea (R. E. Fries) Britton & Rose 1922
Syn. Echinopsis pygmaea R.E. Fries 1905

This variable species has many (>60) synonyms. Current fashion favours Echinopsis.
Native to Bolivia and Argentina.

Lobivia wrightiana

Lobivia wrightiana  Backeberg 1937
Syn. Lobivia backebergii  (Werdermann ) Backeberg 1935 subsp. wrightiana (Backeberg ) G.D. Rowley 1982
Syn. Echinopsis backebergii  Werdermann 1931

Native to the Andes mountains of Peru, growing at up to 9800 ft above sea level.

go to top  Escobaria  Britton & Rose 1923 (Pincushion Cactus, Foxtail Cactus)
Named for: Rómulo Escobar Zeeman (1882 - 1946) & Numa Pompilio Escobar Zerman (1874 - 1949), Mexican agronomists 
Escobaria is a genus of 23 species of small cacti native to North America. The plant bodies are flattened spheroids to short cylindrical columns, without ribs but with prominent tubercles which may become corky and shrivel with age. Spines are never hooked. Flowers in white, yellow pink or purple are produced near to the growing point. Escobaria are similar to Coyphantha but their seeds have a pitted surface rather than a reticulate one.
Native to a large range from Canada into Northern Mexico. A single species is native to Cuba.

Escobaria hesteri

Escobaria hesteri  (Y. Wright) Buxbaum 1951

Photo: South of Marathon, Texas.

Escobaria missouriensis

Escobaria missouriensis  (Sweet) D.R. Hunt 1978

Photograph: Robin Howard, Cheyenne Mountain State Park, Colorado. June 2008

Escobaria tuberculosa - West of Terlingua

Escobaria tuberculosa  (Engelmann) Britton & Rose 1923
This is the type species for the genus.
West of Terlingua, Texas.

Escobaria tuberculosa - Dog Canyon, Big Bend National Park

Escobaria tuberculosa  (Engelmann) Britton & Rose 1923

Photo: Dog Canyon, Big Bend National Park, Texas.

Escobaria strobiliformis seedlings Escobaria tuberculosa - cultivated

Escobaria tuberculosa  (Engelmann) Britton & Rose 1923
Photos: cultivated plants.

Escobaria vivipara

Escobaria vivipara  (Nuttall) Buxbaum 1951 (Spinystar Cactus)

Native to a wide range of Northern America from Canada into Mexico.
Photo: Escobaria vivipara in fruit. Marathon, Texas.

go to top  Ferocactus  Britton & Rose 1922
Name: Latin ferox = fierce + cactus 
The genus Ferocactus includes about 25 species of large barrel cacti with deeply ribbed bodies and strong spines. With age, some species form 10ft columns. Ribs may be straight or tuberculate. The yellow or red flowers are produced around the growing point and are relatively small for the body size. Flower buds are scaly without spines or hairs. The typically-elongated yellow fruits contain many hard black or brown seeds.
Native to the South-Western USA and North-Western Mexico. Many Ferocactus species have extrafloral nectaries above each areole. The nectar is attractive to ants which form colonies around the base of the plant and in return for nectar help to protect the cactus and keep it clean. However, in cultivation exuded sugary nectar makes these species prone to black mould.

Ferocactus acanthodes cristate - Arizona

Ferocactus acanthodes  Britton & Rose 1922
Syn. Ferocactus cylindraceus  (Engelmann) Orcutt 1926

This dustbin-sized Ferocactus has developed a cristate growing point. Nevertheless, it is still flowering and producing fruits.
Photographed in Arizona 2004.

go to top  Gymnocalycium  Pfeiffer ex Mittler 1844
Name: Greek gymno = naked + kalyx = bud 
Gymnocalycium includes about 70 species of small globose, usually solitary cacti. Flower buds are smooth and scaled without spines or hairs.
Native to Argentina, Southern Bolivia, Brazil, Paraguay and Uruguay. These cacti are popular for their brightly coloured flowers.

Gymnocalycium achirasense - Holly Gate Cactus Nursery reference collection

Gymnocalycium achirasense  H.Till & Schatzl 1987
Syn. Gymnocalycium monvillei  Pfeiffer ex Britton & Rose subsp. achirasense (H.Till & Schatzl) H.Till 1993

Native to Northern Argentina.
Photo: Holly Gate Cactus Nursery reference collection

Gymnocalycium friedrichii

Gymnocalycium friedrichii (Werderm.) Pazout 1964 (invalid name)
Syn. Gymnocalycium mihanovichii  Frič ex Gürke) Britton & Rose 1922

Native to Bolivia, Paraguay and Argentina.

Gymnocalycium lafeldense = bruchii

Gymnocalycium lafeldense  Vaupel 1924
Syn. Gymnocalycium bruchii   (Spegazzini) Hosseus 1926

Native to Western Argentina.

Gymnocalycium pflanzii

Gymnocalycium pflanzii  (Vaupel) Werdermann 1935
Named for: Karl Pflanz (1872-1925) German botanist and plant collector. 

Native to Bolivia, Paraguay and Argentina.

go to top  Lophophora  J.M. Coulter 1894 (Peyote Cactus)
Name: Greek lophos = crest + phoreo = to carry 
The genus Lophophora includes up to 4 species of bluish-green to gray button-like cacti with 5 - 8 ribs, whose spines have degenerated into tufts of hairs from each areole.The plant is supported by a large taproot. With age, individual heads can reach 6 in across and can offset at their base to form a clump. Flowers are produced from the growing point and as these plants are self-fertile may be followed by elongated pink fruit.
Native to a range from South-Western USA into central Mexico. In cultivation they are quite free-flowering. These cacti, especially Lophophora williamsii, contain mescaline, pellotine and other toxic alkaloids and feature in Indian-American rituals.

Lophophora williamsii Lophophora williamsii

Lophophora williamsii  (Lemaire ex Salm-Dyck) J.M. Coulter 1894
Named for: Sir. C.H. Williams, British Ambassador to the state of Bahia, Brazil 

Photos: West of Terlingua, Texas.

go to top  Mammillaria  Haworth 1812 (Nipple Cactus)
Name: Latin mammilla = nipple, referring to the distinctive tubercles. 
The large genus Mammillaria includes 171 species of small cacti with distinctive tuberculate aereoles, the apex of which bears spines and the base of which is spineless but may be woolly or have bristles. The base of the aereole also bears the flowers and fruits. The spines are quite variable between species and may be straight or hooked. Most species are spheroidal, or with age form short columns up to 8 inches tall. Many species have small pink flowers, or small yellow or white flower. Just a few have relatively large showy flowers. Flowers are typically folllowed by small, tubular red fruit.
Most Mammillaria are native to Mexico but also to the South-Western USA, the Caribbean islands, Colombia, Guatemala, Honduras, and Venezuela. This genus of cacti is popular and easy in cultivation and many species flower freely on a sunny window ledge.

Mammillaria bocasana (pink flower) - cultivated Mammillaria bocasana (yellow flower) - cultivated

Mammillaria bocasana  Poselger 1853
This fast-growing, clumping cactus has tubercles with a single fish-hook spine surrounded by a cluster of long silky hairs. Flowers may be pink or yellow.
Native to central Mexico.
Extreme left: Pink flower. Holly Gate Cactus Nursery reference collection.
Left: Yellow flower.

Mammillaria glassii - cultivated

Mammillaria glassii R.A. Foster 1968
Named for: Charles Edward Glass (1934-1968) American horticulturalist & plant collector 

Native to the Mexican state of Nuevo León.

Mammillaria gracilis - cultivated

Mammillaria gracilis  Pfeiffer 1838
Syn. Mammillaria vetula subsp. gracilis (Pfeiffer) D.R. Hunt 1997

Native to the Mexican state of Hilalgo.
Various selected spine variants are in cultivation e.g. "Arizona Snowflake / Snowcap".

purple-dyed Mammillaria gracilis

Mammillaria gracilis, possibly the cultivar "Arizona Snowflake / Snowcap"
dyed purple and marketed under the trade name Kosmic Kaktus.
A range of other colours are available. Any new growth will have the
gleaming white spines of the original plant so if you buy one of each
colour, those that grow will eventually all look the same.
Photo: Andrea Hüper, 2014.

Mammillaria grusonii - Holly Gate Cactus Nursery reference collection

Mammillaria grusonii  Runge 1889
Named for: Hermann August Jacques Gruson (1821 - 1895) German engineer & cactus collector 

Native to the Mexican states of Coahuila and Durango.
Photo: Holly Gate Cactus Nursery reference collection

Mammillaria hahniana - Holly Gate Cactus Nursery reference collection

Mammillaria hahniana  Werdermann 1929

Native to the central Mexican states of Guanajuato, Querétaro Arteaga and Tamaulipas.
Photo: Holly Gate Cactus Nursery reference collection

Mammillaria heyderi - in fruit, Dog Canyon, Big Bend National Park, Texas.

Mammillaria heyderi  Muehlenpfordt 1848

Photo: in fruit, Dog Canyon, Big Bend National Park, Texas.

Mammillaria heyderi var meiacantha - West of Terlingua, Texas.

Mammillaria heyderi subsp. meiacantha  (Engelmann) D.R. Hunt 1997

Photo: West of Terlingua, Texas.

Mammillaria microhelia - cultivated

Mammillaria microhelia  Werdermann 1930

Native to the Mexican state of Querétaro.

Mammillaria prolifera - cultivated

Mammillaria prolifera  (Miller) Haworth 1812 (Texas Nipple Cactus)

Widely distributed from Texas into the Mexican states of Coahuila, Nuevo León, Querétaro, San Luis Potosí & Tamaulipas. Also in Cuba, Dominican Republic & Haiti.
Photo: cultivated plant.

Melocactus  Link & Otto (Turk's cap cactus)
Name: Latin Melus = melon + cactus 
The genus Melocactus includes about 40 species of cacti from the Carribean, Mexico and South America. Juvenile plants have globose green bodies with 8 - 27 prominent ribs and stout spines. As these plants mature the main stem ceases growth and they develop a cephalium consisting of a dense mass of areoles with short spines at the apex of the plant. This structure may keep growing for years, in some species exceeding the size of the main body. The cephalium is often orange but may be white and produces many small, often pink flowers. Flowers are followed by waxy pink or red fruits like miniature candles.
Native to a range including the Carribean Islands, Western Mexico, central America, Brazil to Southern Peru. In cultivation a Melocactus requires constant warmth to prevent marking or collapse.

Melocactus peruvianus - RBG Kew

Melocactus peruvianus  Vaupel 1913
Name: refers to presence of plant in Peru 

Native to Ecuador and Peru. Photographed at RBG Kew.

Melocactus zehntneri - RBG Kew

Melocactus zehntneri  (Britton & Rose) Luetzelburg 1923
Named for: Leo Zehntner (1864 - 1961) Swiss entomologist & botanist 

Native to North-Eastern Brazil. Photographed at RBG Kew.

Myrtillocactus  (von Martius) Console 1897
Name: the fruits resemble those of Bilberry (Vaccinium myrtillus) 
The genus Myrtillocactus includes 4 species of shrubby, tree-like (25 ft) cacti with few (4-8) ribs and frequently-branching glaucous-green stems. Areoles may be without spines or have a single long, thick central spine with a few short, stout radial spines. Each areole can produce several greenish-white, waxy flowers less than 1 in long, and with short floral tubes. Flowers are followed by edible berries.
Native to Mexico including Baja California to Guatemala.

Myrtillocactus cochal - RBG Kew

Myrtillocactus cochal  (Orcutt) Britton & Rose 1909 (Candelabra Cactus)
Name: 'cochal' is the common name for this plant 
Myrtillocactus cochal grows as dense shrubs up to 12 ft tall with a short woody trunk bearing many six to eight-ribbed branches. Areoles have a long central spine with five shorter radial spines. The small flowers are greenish-white and followed by edible maroon berries.
Native to Baja California. Photographed at RBG Kew.

Myrtillocactus geometrizans - RBG Kew

Myrtillocactus geometrizans  (von Martius) Console 1897   (Bilberry Cactus, fruit = Garambullo)
Name: Latin geometricus = geometric, referring to the architectural stems 
The robust nature of Myrtillocactus geometrizans makes it suitable for grafting stock, although it is not cold-hardy. Each areole can produce several brownish buds that open into greenish-white, waxy flowers less than 1 in long, and with short floral tubes. Flowers are followed by edible, blue berries which are harvested for sale in Mexican markets.
Native to Mexico including Baja California to Guatemala and widely cultivated. A cristate form is commonly seen in cultivation. Photographed at RBG Kew.

go to top  Oreocereus   (A.Berger) Riccob.
Name: Greek oros = mountain + Latin cereus = candle 
This genus includes 9 species of short columnar cacti with ribbed bodies that are covered in white hairs that are degenerate radial spines. Sharp central spines extend beyound the hairs. The tubular flowers are usually pink to red or orange.
Native to elevations of at least 10,000 ft in the Andes of Argentina, Bolivia, Chile, and Peru. The wooly covering doubtless protects against the harsh light and cold nights, but is probably also important for harvesting moisture from fogs that condenses on the hairs.

Oreocereus trollii - cultivated

Oreocereus trollii  Kupper 1929 (Old Man of the Mountain / Andes)
Syn. Borzicactus celsianus var. trollii (Kupper) G.D.Rowley 1986
Named for: Carl Troll (1899 - 1975) German botanist & geographer 
This short (2 ft) columnar cactus has a ribbed body that is densely coated in matted white hairs with protruding brown spines. Mature plants clump up by basal offsetting. The tubular flowers are violet-red to pink.
Native to Andes mountains of Northern Argentina and Southern Bolivia growing at elevations of up to 14,000 ft above sea level. Popular in cultivation but needs careful watering to avoid the white hairs wicking up salts and becoming dicoloured. Avoid watering during cold weather and Winter.

go to top  Pachycereus  (A. Berger) Britton & Rose 1909
Name: Greek pakhus = thick + Latin cereus = candle 
The are 9 - 12 species of Pachycereus, whose stout ribbed stems form columnar shrubs and very large tree-like cacti branching well above the ground to form a candelabra. Young growth is often fiercely spined, but mature growth above the reach of herbivores much less spiny. The large tubular flowers have a hairy or scaly brownish outer surface and white to pale pink interiors.
Native to Mexico, Baja California and the Southern edge of Arizona. Pachycereus pringlei (Cardon) is fairly common in cultivation. Some species contain toxic, psychoactive alkaloids.

Lophocereus schottii

Lophocereus  (A. Berger) Britton & Rose 1909
Plants in this genus have been transferred to Pachycereus.

Pachycereus schottii  D.R. Hunt 1987 (Senita Cactus)
Syn. Lophocereus schottii Britton & Rose 1909
Mature flowering stems develop a pseudocephalium of long, hairlike, grey spines towards their ends.
Photograph: Organ Pipe Monument Az.

go to top  Parodia  Spegazzini 1923
Named for: Lorenzo Raimundo Parodi, Argentine biologist 
The genus Parodia includes about 50 species of globular cacti, some of which elongate into short columnar plants. All species have deep ribs furnished with spines along their edge and usually single yellow or red flowers near the growing point, produced throughout the year.
Parodia are native to Argentina, Brazil, Colombia, Paraguay, Peru and Uruguay. The genus was expanded by transfer of species from the genera Eriocactus, Notocactus and Wigginsia. These free-flowering cacti are popular and easy to grow in a sunny place.

Notocactus  (K.M. Schumann) Frič 1928 Name: Greek = cactus of the south 
The 25 species from the obsolete genus Notocactus were moved into the genus Parodia in the 1980s but the name persists in books and plant labels. Notocacti have globose bodies elongating into short columns. The relatively large, funnel shaped flowers in yellows and red are produced throughout the year, each flower usually lasting several days.
Notocacti are native to lowlands of Argentina, Paraguay, Uruguay, and Southern Brazil.

Parodia magnifica - cultivated

Parodia magnifica   (Ritter) F. H. Brandt 1982
The spherical to columnar blue-green plant body has dense yellow to brown spines and hairs along its ribs. Old plants clump up by offsetting. Flowers are pale yellow at the apex of the cactus.
Native to Southern Brazil, Paraguay, Uruguay and Argentina.
Photo: a very old clump at RBG Kew.

Notocactus succineus - cultivated

Notocactus succineus  F. Ritter 1970 (Silver Ball Cactus)
Syn. Parodia scopa subsp. succinea (F. Ritter) Hofacker & P.J. Braun 1998

go to top  Peniocereus  (A. Berger) Britton & Rose 1909 (Night-Blooming Cereus, Queen of the Night)
Name: Latin penis = tail + Latin cereus = candle  
The genus Peniocereus includes about 8 species of cacti from the South-Western USA and Mexico. A very large underground tuber supports long thin stems that scramble through other supporting bushes. Flowers typically open during the night.
Wilcoxia viperina

go to top  Wilcoxia  Britton & Rose 1909
Named for: Timothy E. Wilcox, US General  
Some species of Wilcoxia have been transferred to Peniocereus and the genus Wilcoxia
has been reduced to Echinocereus section Wilcoxia (Britton & Rose) N.P. Taylor.

Wilcoxia viperina
Syn. Peniocereus viperinus

go to top  Rebutia  K. Schumann 1895
Named for: Pierre Rebut (1827 - 1898) French vine grower, cactus collector & nursery owner.
The genus Rebutia consists of small globular free-flowering cacti native to Boliva and Argentina. The bodies do not have ribs but regularly-arranged tubercles. Most species form clumps by offsetting from their base. The red, orange, yellow and white flowers are relatively large compared to the plant body and appear to be self-fertile, producing seed which may germinate around the plant. Because of repeated splitting and lumping of genera, and transfer of some species into Lobivia / Echinopsis the number of species of Rebutia is indeterminate, but probably in the range 12 - 40 species.
Species that were formerly in the genus Weingartia have been lumped into Rebutia.
These popular cacti are easy to grow and flower freely on a sunny window-ledge. Several hybrids are in circulation.

Rebutia albiflora

Rebutia albiflora  Ritter & Buining 1963
Named for: Latin albi = white + flora = flower 
This clumping cactus has small globose stems covered with soft radial spines. The relatively large (1 in diameter) flowers are white to pinkish-white with an externally pink flower tube and are followed by dry red fruits.
Native to South-East Bolivia.

Rebutia heliosa x albiflora

Rebutia heliosa x albiflora
An attractive, free-flowering hybrid that quickly forms a mat of small, globular plant bodies. As with many hybrids, some variation is seen in the flower colours and selected forms have been propagated with flower colours from pale pink to peach.

go to top  Rhipsalis  Gärtner 1788 (Mistletoe Cacti)
Name: Greek rhips = wickerwork, refering to slender, flexible stems. 
Rhipsalis is the largest genus of epiphytic cacti. The succulent photosynthetic stems may be cylindrical, angular of flattened and vary considerably in thickness. They usually branch frequently. R. pilocarpa is unique in having stems that are densely covered in areoles with bristles. In all other species, spines are absent or only on juvenile growth. Flowers are usually small and white, occasionally yellow and red in one species (R. hoelleri.)The fruits are white, pink, red or yellow berries.
With the exception of Rhipsalis baccifera all species are native solely to tropical rainforests of South America, especially Brazil, and to the Carribean.

Rhipsalis baccifera (J.S. Mueller) Stearn 1939 (Mistletoe Cactus)
This is a variable species with a wider natural distribution than any other cactus. South American plants are diploid but those from Mesoamerica, the Carribean and elsewhere are tetraploid. R. baccifera is found also in tropical rainforests of Africa, Madagascar, Seychelles, Mauritius, Reunion, India and Ceylon. As R. baccifera is not ancestral to Cactaceae and unlikely to have evolved before separation of the continents, this pandemic distribution may reflect transport by migratory birds or humans, perhaps for the sweet berries.

Rhipsalis baccifera ssp. mauritiana

Rhipsalis baccifera ssp. mauritiana  (De Candolle) Barthlott 1987 (Mistletoe Cactus)
This sub-species from the Indian Ocean area is tetraploid with 44 chromosomes. The white berries are edible and larger than those of the diploid sub-species.

Rhipsalis cereoides

Rhipsalis cereoides  (Backeberg & Voll) Backeberg 1937
This cactus grows mainly as an epiphyte. The three (occasionally four) -cornered stems are joined end to end, often branching at the sttem joints. Small areoles with a few bristles can be found along the stems. The small white flowers appear from the areoles in groups and are followed by red transluscent fruit.
Native to rainforests of Brazil.

Rhipsalis pilocarpa Rhipsalis pilocarpa

Rhipsalis pilocarpa   Lofgren 1903
Name: Latin pilus = hairy + carpus = fruit 
The long thin branching stems are distinctively covered in fine hairs growing from otherwise spineless areoles. In mid-Winter, bell-like white flowers are produced at the ends of the stems. The interiors of the flower tunes may be tinged with pink. Flowers are followed by red berries whose surface has areoles bearing tufts of hairs.
Native to Brazil. This is an ideal plant for a shady corner of the greenhouse or conservatory.

go to top  Schlumbergera  Lemaire 1858 (Christmas Cactus)
Named for: Frédéric Schlumberger (1823 - 1893) French cactus grower from Anthieux 
The genus Schlumbergera includes 6 species of epiphytic cacti from South-Eastern Brazil. The stems are formed from flattened, jointed segments that resemble fleshy leaves. Pink flowers arise from areoles at the stem joints and notched tips of the stems and are bird pollinated. Tiny vestigial spines can also be found in these places.
By selection and hybridization, plant breeders have produced many varieties with different forms and flower colours. Flowering is controlled by temperature and short day length.

Zygocactus truncatus

Zygocactus  Schumann 1890
The obsolete genus Zygocactus is included in Schlumbergera.

Schlumbergera truncata  (Haworth) Moran 1953
Syn. Zygocactus truncatus  (Haworth) K. Schumann 1890 (Christmas cactus)
The traditional "Christmas Cactus" is a hybrid Schlumbergera x buckleyi with a magenta flower. The wild form of Schlumbergera truncata in Brazil has a red flower. A range of hybrids with flowers in other colours have become available recently.

go to top  Sclerocactus  Britton & Rose 1922
Name: Greek sclero = hard referring to fruit + cactus  
The genus Sclerocactus includes about 15 species of particularly xerophytic cacti from North America. Plant bodies are globular to short columns with tuberculate ribs and dense spination. Most species have at least one hooked spine at each areole but a few species do not have hooks. Funnel-shaped flowers in shades of pink, yellow, and greenish are produced near to the growing point.
Native to the Southern USA and Northern Mexico.
The genera Ancistrocactus, Echinomastus, Glandulicactus and Toumeya are lumped into Sclerocactus by some authors.

Sclerocactus parviflorus Sclerocactus parviflorus

Sclerocactus parviflorus  Clover & Jotter 1941 (Devil's Claw Cactus)
Name: Latin parviflorus = small flowers, perhaps not entirely appropriate 

Extreme left: Robin Howard, Cheyenne Mountain State Park, Colorado. June 2008
Left: Robin Howard, Colorado Springs, Colorado. June 2008

Toumeya papyracantha - salt flats, Texas.

Toumeya  Britton & Rose 1922
Named for: James W. Toumey (1865 - 1932) Dean of School of Forestry, Yale University (1919 - 1922) 
The genus Toumeya was merged into Sclerocactus  Britton & Rose 1922.

Sclerocactus papyracanthus (Engelmann) N.P. Taylor 1987 (Paper-Spined Cactus)
Syn. Toumeya papyracantha  Britton & Rose 1922
Photograph: gypsum salt flats in front of Guadalupe Mountains, Texas.

go to top  Selenicereus  (A. Berger) Britton & Rose 1909 (Moonlight Cacti)
Named for: Selene, Greek moon goddess + Latin cereus = candle, referring to nocturnal flowering  
The genus Selenicereus includes 28 species of climbing or scrambling epiphytic cacti with flat to angled stems producing aerial roots and often rooting where they touch a suitable substrate. Stems may be spiny or without spines. The funnel-shaped flowers are usually large, white, yellow to pink and very fragrant, tending to be nocturnal. Fruits are fleshy and covered with spines. Hylocereus megalanthus - Yellow Pitahaya
Native to rain forests of the Carribean and central to South America.
Hylocereus megalanthus Syn. Selenicereus megalanthus (Yellow Pitahaya) widely cultivated commercially for its fruits, may be a hybrid between Hylocereus and Selenicereus.

Selenicereus anthonyanus

Selenicereus anthonyanus (Alexander) D.R. Hunt 1989 (Fish Bone Cactus)
Syn. Cryptocereus anthonyanus  Alexander 1950
Named for: Dr. Harold E. Anthony (1890 - 1970) American zoologist & paleontologist, first to flower this plant 
The notched stem may be an adaptation to the low light levels under the rainforest canopy, by increasing the area of the photosynthetic stem instead of producing leaves. The large fragrant flowers open for just one night.
Native to the rainforests of Chiapas, Oaxaca, Tabasco and Veracruz, Mexico.

Selenicereus grandiflorus

Selenicereus grandiflorus  (Linnaeus) Britton & Rose 1909 (Queen of the Night)
Name: grandiflorus = large flowered 
The large fragrant white flowers open for less than one night.
Native to Cuba, Cayman Islands, Jamaica, Haiti, Puerto Rico, Mexico, Belize, Guatemala, Honduras and Nicaragua.

go to top  Stenocactus  (Schumann) Berger 1929  Syn. Echinofossulocactus Britton & Rose 1922
Name: Greek steno = tight or narrow, referring to the ribs. 
This genus includes 11 species of mostly solitary, small globular cacti up to 4 in in diameter, with strong fin-like ribs and prominent spination. Small funnel-shaped flowers are produced near to the growing point of the plant and are often pale with a darker longitudinal stripe.
Native to the Chihuahuan desert of Mexico. Most Stenocactus grow easily and are free-flowering.
Echinofossulocactus is a synonym of Stenocactus.

Stenocactus crispatus - Holly Gate Cactus Nursery reference collection

Stenocactus crispatus  (de Candolle) A. Berger ex A. W. Hill 1933
Name: Latin crispus = with wavy margins, referring to the ribs. 

Widely distributed in the Mexican states of Guanajuato, Hidalgo, México Distrito Federal, México State, Oaxaca, Puebla, Querétaro, San Luis Potosí, Tamaulipas, Tlaxcala and Veracruz.
Photo: Holly Gate Cactus Nursery reference collection

Stenocactus multicostatus - Holly Gate Cactus Nursery reference collection

Stenocactus multicostatus  (Hildmann ex K. Schumann) A. Berger 1929
Syn. Echinofossulocactus multicostatus (Hildmann ex K. Schumann) Britton et Rose 1922

Native to the Mexican states of Aguascalientes, Coahuila, Durango, Guanajuato, Jalisco, Nuevo León, Querétaro, San Luis Potosí, Tamaulipas and Zacatecas.
Photo: Holly Gate Cactus Nursery reference collection

go to top  Thelocactus  (K. Schumann) Britton & Rose 1922
Name: Greek thele = wart or nipple + cactus  
The genus Thelocactus includes up to 15 species of small globular cacti with ribbed bodies, usually with angular tubercles. Areoles have up to 20 fine radiating spins with up to 6 stronger central spines which are sometimes hooked. These plants often have colourful spines in white, gray, yellow and reddish-brown. Funnel-shaped, relatively large white, yellow, red or magenta flowers are produced at the apex of the plant.
Native to Texas and Northern to central Mexico. Most species are solitary but some will clump up.
The genus Hamatocactus is now included in Thelocactus.

Thelocactus bicolor (Galeotti ex Pfeiffer) Britton & Rose 1922
Native to a range from Texas into central Mexico.

Thelocactus bicolor var flavidispinus Thelocactus bicolor var. flavidispinus

Thelocactus bicolor var. flavidispinus  (Backeberg) N.P. Taylor 1998 (Glory of Texas)
Name: flavidispinus = yellow spined 

Native to Big Bend Country, Texas into Mexico.
Extreme left: West of Terlingua, Texas.

go to top  Weingartia  Werdermann 1937
Named for: Wilhelm Weingart (1856 - 1936), German amateur cactus expert and close friend of Werdermann 
Weingartia is a genus with 60 species of globular to shortly-cylindrical cacti with 12 - 18 tuberculate ribs arranged as a spiral. Yellow to orange funnel-shaped flowers are produced near to the growing point with up to 3 flowers per areole.
Native to the Andes of Southern Bolivia and North-West Argentina at elevations of up to 12,500 ft. Some authors have lumped Weingartia into Rebutia, with three-quarters of the species as synonyms of R. canigueralii and R. neocumingii, but this is still controversial.

Weingartia neocumingii var neocumingii

Weingartia neocumingii var neocumingii  Backeberg 1950
Syn. Rebutia neocumingii (Backeberg) D.R. Hunt 1987

Photos left and below: Some very old plants at Holly Gate Cactus Nursery reference collection.

W. neocumingii var riograndensis
  var. riograndensis
Weingartia neocumingii var sucrensis
  var. sucrensis
Weingartia neocumingii var trollii
  var. trollii