Neochilenia - October 2006

Neochilenia and Neoporteria are now included in the genus Eriosyce. The genus  Neoporteria  was named after the Chilean entomologist and naturalist Carlos Porter.  

Eriosyce used to be a very little genus. It now includes Chileorebutia, Delaetia, Horridocactus, Islaya, Neochilenia, Neoporteria, Pyrrhocactus, Rodentiophila, and Thelocephala. All the species still come from Chile, and vary in shape from globular to shortly columnar. The name 'Eriosyce' comes from the Greek for woolly 'fruit'.

Many of the species have a tap root, and most are rot prone, and particularly the dwarf species. The potting soil used should have an excellent drainage. They generally take some frost for a short period of time.

Recommended Temperature Zone: USDA: 9b-11 Minimum Avg. Temperature: 50°F (10°C)
Sun Exposure: Full sun to light shade
Origin: Chile (Elqui Valley)
Growth Habits: Globose to cylindrical, up to 8 inches tall (20 cm), 5 inches in diameter (13 cm)
Watering Needs: Extremely root prone, needs good drainage.
Propagation: Seeds

Photo in Cactus Chronicle:
Eriosyce (neochilenia) kunzei
Information courtesy of www.desert-tropicals.com

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Neoporteria - October 2006

Recommended Temperature Zone: USDA: 9b-11 Minimum Avg. Temperature: 20°F (-7°C)
Sun Exposure: Full sun to light shade
Origin: Chile (Atacama)
Growth Habits: Globose to short columnar stem, up to 1.5 inches in diameter (4 cm), 2.4 inches tall (6 cm); very large tap root; larger tubercles than ssp. lembckei; short black radials
Watering Needs: Needs deep pot and good drainage to accommodate its tap root
Propagation: Seeds

see Neochilenia above for more info.

Photo in Cactus Chronicle:
Eriosyce (neoporteria) napina
Information courtesy of www.desert-tropicals.com

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Nolina - April 2014, June 2007

​ . . . the characteristics of being woody and having grass-like to sword-like leaves. Cultivation of most species is easy. Nearly all can grow in the ground, and most, but the largest species, can live happily in pots. They are mainly warm season growers so provide some water during the spring through fall to get them to look their best.

Nolina, like Yucca, has species native to the United States (including in our area of California). They are very closely related to Beaucarnea but differ in technical features of the fruit. While all Beaucarnea form woody trees, Nolina often form big clumps of grassy to sword shaped leaves. Some large, mature Nolina can form a big mostly unbranched trunk and look remarkably similar to the Australian Grass Trees, Xanthorrhoea.
-- Kyle Williams
Photo in Cactus Chronicle:
Nolina parryi

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Notocactus - April 2016, October 2009, February 2007

What we call Parodia today is an assemblage of cactus species formerly spread out amongst the genera Parodia, Brasili-cactus, Brasiliparodia, Eriocactus, Wigginsia, and most notably Notocactus.  In other words, if you have a cactus with any of those genus names you should now call them Parodia. Botanists have determined that all these genera contain species so similar and closely related to each other that there is no meaningful and reliable way to tell the genera apart. For example, a major way of separating these supposedly different genera was to look at the color of the stigma (the female part of the flower) and details of how seeds were attached to the inside of the fruit. These are such minor and inconsistent details that it isn’t reasonable to keep them apart.
-- Kyle Williams

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 Los Angeles Cactus and Succulent Society
 Los Angeles Cactus and Succulent Society

Obregonia - August 2014

Obregonia is a monotypic genus (i.e. a genus with only one species) containing the species Obregonia denegrii from a small region of Tamaulipas, Mexico. This plant gets its name from a fairly shameless attempt to impress both the President of Mexico, Mr. Obregon and the Agriculture Minister of Mexico, Mr. Denegri, at the time the plant was discovered. If you are going to have a cactus named after you this is one of the better ones as Obregonia is one of the most unusual and coveted cacti in cultivation. The common name "Artichoke Cactus" belies this. The plant forms unusual leaf like tubercles that really do resemble an artichoke, though this is much slower growing and you wouldn't want to eat it! For a long time this species was quite rare and expensive in cultivation. In recent years the price has come down quite a bit as more and more plants are produced. While certainly not common, you can find it fairly readily at cactus shows and through specialist cactus nurseries.

Plants are slow growing but cultivation isn't particularly difficult. Plants grown in shady conditions are usually green, but give them more light and they will become a beautiful bronze color. Because they are slow growing and tuberous rooted they can be prone to rot, especially in the winter, if kept too moist. Treat it like an Ariocarpus and you will be fine.

Photo in Cactus Chronicle:
Obregonia denegrii
-- Kyle Williams

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Opuntia - July 2007
from South America - March 2014
from North America - September 2017, July 2013

Opuntia is one of the largest genera of the Cactaceae (cactus family) and is the most common type of cactus in North America. Plants in this genus form jointed stems that to many look like leaves (but aren't). The most distinctive (and reviled) feature of Opuntia are "glochids", tiny hair like spines that stick in your skin even if you just brush against the plant lightly. Always have tweezers ready when Opuntia are near! Jointed stems and glochids are found in most of subfamily Opuntioidiae, which consists of Opuntia and several closely related genera (see below).

For the sake of the "Plant of the Month" we will include North American Opuntia (including Mexico & the Caribbean) and closely related genera. These additional genera include Cylindropuntia, Consolea, Pereskiopsis, Cornyopuntia, and Grusonia.

Opuntia (in the broad sense) covers the largest geographical range of any cactus genus, stretching from Southern Argentina to Canada, covers all of the Caribbean Islands and Pacific Islands, from the Galapagos to the Catalinas. It is naturalized on every continent except Antarctica. It is a pest and a noxious weed in many places, and is displacing native vegetation in parts of Africa, Asia, Madagascar and Australia.

The vast majority of North American Opuntioideae species belong to just two genera: Opuntia and CylindropuntiaOpuntia, commonly called “Prickly Pears” have pads which are actually flattened, jointed stem segments. They are NOT leaves. No other cacti (outside of some very closely related Opuntioid genera) have this growth form. Cylindropuntia was formerly included in Opuntia but is fairly easy to distinguish by its round jointed stems. They are commonly called Chollas and some species are famously called “jumping Chollas” because the spiny stem segments break off (“jump”) very easily and stick to animal fur, clothing, or even right in our skin. Aside from the unusual Pereskiopsis which has true leaves, the other North American genera closely resemble these two main genera. For the sake of Plant of the Month, Cylindropuntia is exclusively North American, but Opuntia is not. So do a quick Google search for the name of your Opuntia to check for sure.

 Taxonomy in is very complicated in this group and some botanists consider everything Pereskiopsis to all be Opuntia (of these North American genera), though most are also accepting of Cylindropuntia. Most of the recent changes in the Opuntia group is due to recent DNA phylogeny studies of the species.

Handling of Opuntias is somewhat of a problem due to their glochids. Handling with steel tools is the best bet. Leather and cloth gloves get covered with glochids, which invariably end up in your hands when the gloves come off. However, the modern neoprene gardening gloves work great. Plucking with tweezers is effective and brushing works sometimes. Duct tape is a help, and as a last resort, so is rubber cement.
 — Kyle Williams

Photos in Cactus Chronicle:
Opuntia basilaris, Opuntia ’Sunburst’, Cylindropuntia ramosissima  

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Oreocereus - October 2018, June 2009

Oreocereus is another very popular South American columnar cactus that is found in Bolivia and Northern Argentina. Also known as the Old Man of the Andes, most species of Oreocereus form prostrate cluster or bush-like spreads of erect columns. Oreocerus celsianus (pictured in June 2009 Chronicle) is a specimen that can grow to 10 feet tall and look tree-like in appearance. The mature plant is covered with red or straw-colored spines. The flowers produced by this plant are red-violet. Oreocereus doelzianus is a less popular plant that grows in an entirely different manner. Species of this plant reach only 3 feet and are approximately 3 inches in diameter. This plant forms clumps in habitat that are covered with downy white areoles from which protrude sharp spines. This species produces a tubular shaped crimson flower. 

Columnar cacti are not a botanically or taxonomically related genera; they are instead a grouping of all the cacti that grow in a columnar manner.  They are robust growers, given adequate water, fertilizer, root room and support. They expect more nitrogen in their soil and more water than most globular cacti, when they are growing. They do well in normal cactus mix, as long as they get additional fertilization.
D C. Zappi, Pilosocereus
D. Hunt, The New Cactus Lexicon
Tom Glavich, August 2004 - Edited by Steven Frieze, 2009

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Oroya - July 2018, February 2013, October 2007

Oroya is a Peruvian cactus, found in the Western foothills and lower mountain slopes and valleys of the Andes. These plants are not as well known as many other South American cacti, even though they have wonderful body colors, spines and flowers. Oroya grows quite a bit slower than Matucana. They are not difficult plants. The general culture is similar to most other South American cacti. They need water when growing in the summer but need to be kept dry when cold. They do fine, unprotected in Southern California winters.

Oroya was also described by Britton and Rose, on the same page as Matucana.  This genus has only two or three species. The type is Oroya peruviana, the genus again named after a nearby town. The type was known by a different name since 1903.  

In habitat Oroya is a flattened globe, with only the upper surface usually visible. In cultivation the plant shows off a beautiful spiral pattern of spines, with geometric precision equal to any Mammillaria.
-- Kyle Williams​
Photo in Cactus Chronicle:
Oroya Peruviana

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Ortegocactus - January 2011

Ortegocactus macdougalli is endemic to Oaxaca, Mexico and grows on limestone rock cropping at heights up to 6,000 feet.  It is a monotypic cactus.

Closely related to the genus Mammillaria, this plant is often grafted to avoid growing difficulties associated with its own root system. Another potential problem with Ortegocactus is the orange discolorations that frequently appear at the base of stems.

Photo in Cactus Chronicle:
Ortegocactus macdougalli
D. Hunt, The New Cactus Lexicon, C. Innes and C. Glass, Cacti
Steve Frieze, January 2011

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Othonna - January 2018 & 2012 & 2010

​Othonna, with over 100 species, would be considered a large genus in most circumstances.  They are winter growing plants from the winter rainfall areas of Namibia and western South Africa. They are variable in form, with the most popular kinds having attractive caudiciform bases. Other types have fat elongated stems while others are geophytes which make annual stems that come up in the winter and die to the ground in the summer. Most make nice yellow daisy-like flowers. Cultivation of the woody species is very similar to Tylecodon or other woody winter growers, while the geophytic species can be treated similar to winter growing bulbs such as Albuca.
-- Kyle Williams

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Oxalis caudiciform - January - February 2009

research in progress

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Pachycormus - May - June 2008, March 2008, June 2007, March 2007

research in progress

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Pachypodium - May - June 2008, June 2007
   Africa - July 2017, August 2011
   of Madagascar - July 2015
   not Madagascar - September 2009

The vast majority of species (all but a handful of the 25-30 species) occur only on Madagascar. Some species look like they come from a desert (e.g. P. brevicaule), while many others would look as much at home in a tropical landscape as a desert one (e.g. P. lamerei).  Madagascar really is a tropical island, just one with deserts, rainforests, and everything in between!  In particular, the amazing Traveler's Palm (Ravenala madagascariensis), a close relative of the Bird of Paradise (Strelitzia)

of Madagascar

 . . . every Pachypodium species except: P. namaquanum, 
P. succulentum (including P. griquense), P. bispinosum, P. saundersii & P. lealii. 

Pachypodium belongs to the Apocynaceae, one of the largest of all plant families as well as one of the families with the most species of succulents. It is closely related to Adenium, StapeliadsFockea, Oleanders, Milkweeds, Plumeria, and many other non-xeric plants. While most similar to Adenium, Pachypodium can be distinguished from it by having spines, and usually by flower color. While pinks and reds are extremely common in Adenium, only a few Pachypodium have red or pink in their flowers. Pachypodium also stands out from most of the family, including Adenium, in having alternate leaves (one leaf at each node) while the rest of the family (usually) has opposite leaves (paired leaves).

Have you ever given thought to how plants end up where they are and why some places have more species than others? The distribution of Pachypodium may lead you to consider that. Why are there so many more (4 - 5x) as many species in Madagascar than in the whole of continental Africa? It must be because Pachypodium evolved in Madagascar, right? Possibly, but it is equally likely that it evolved in Africa but didn't diversify greatly there, but when a single plant arrived in Madagascar it rapidly spread around the island then became isolated in different habitats which over time evolved into different species. In other words, a center of diversity for a plant group today doesn't necessarily mean that's where the group originated. In one location the conditions may have allowed for tall, tree like, species to form (e.g. P. lamerei & P. geayi) while in other places, such as very dry rocky hills, small very xeric species may have been better adapted. Yes, Africa also has lots of different habitats, but it may have had to compete with many other plants already there while Madagascar might have had less plants at the time, making it easier for Pachypodium to thrive and diversify. Recent research into the relationships of Pachypodium suggest this may well be what happened!

Cultivation of Pachypodium is generally easy. Most like constant moisture (not wet!) during the growing season. When they drop their leaves in the winter keep dry. Some species, like P. brevicaule are more water sensitive than others. The biggest difference between African and Madagascar species is in cold tolerance. In general, African species can tolerate more cold, while Madagascar species need to at least be kept above freezing, with some species only thriving if kept above 50 degrees. P. lamerei is the biggest exception in that it is a Madagascar species that can tolerate the occasional light frost in our region.

Photos in Cactus Chronicle:
 Pachypodium makayense, Pachypodium geayi, Pachypodium baronii,
-- Kyle Williams

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Parodia - April 2016, October 2012, February 2007

The genus Parodia now incorporates the genus Notocactus, and in modern references, all Notocacti have been moved into Parodia. The number of species has also been greatly reduced. The original distinguishing characteristic was the red stigmas in the flowers of Notocactus, and the yellow stigma in those of Parodia. The distinguishing characteristic between the two genera evolved over time, eventually becoming a minor difference in the attachment of the seed to ovary. Parodia has swept up several other genera, and is likely to grow and swallow a few more as botanical and genetic studies continue.  Nonetheless, the two are separate in many seed catalogs, in older reference books, in our shows, and in most of our collections.

Notocactus are South American Cacti, with the genus being centered in Brazil and Argentina. Members of this genus are also spread throughout the Eastern side of the Andes. This genus is easy to grow, growing freely in the spring through the fall, and going more or less dormant in the during the colder months. Some species will flower in mid-winter, and given their native environment, most do better given a little water year around. If watering Notocactus in the winter, avoid fertilization or weak growth may result. Some of the more tropical species need protection from colder weather to prevent scarring, but most will take normal Southern California winters without protection.

All the species are easy to grow from seed. Seed is available for nearly all the species and from many localities. Fresh seed germinates readily and can grow to a show quality plant in just a few years. Vegetative propagation of the clustering types is easy as well. Cuttings taken during the late spring and early summer root readily and show new growth before the season is over.

The genus Parodia are typically globular to cylindrical plants with pronounced ribs. Flowers emerge from the apex of the plant, normally are self-fertile and are generated during the spring and summer. The genus was named for Argentinean botanist, L. R. Parodia. The genus Notocactus was folded into Parodia relatively recently and this genus also is synonymous Malacocarpus, Brasilicactus, and Wiggninsia. The genus Parodia now incorporates sixty six species and can be found in habitat in South America (Brazil, Bolivia, Uruguay, Argentina).

Photos in Cactus Chronicle:
 Notocactus magnificus, Notocactus leninghausii crest, 
Parodia ottonis, Parodia formosa
D. Hunt, The New Cactus Lexicon; C. Innes & C. Glass, Cacti
Tom Glavich February 2003 - Edited by Steve Frieze, 2012

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Pedilanthus - October 2018, July 2007

the genus Pedilanthus has been submerged into the genus Euphorbia.

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Pediocactus - March 2015, September 2008 & 2007

Pediocactus has a similar number of species as Echinomastus. It had long been thought to be closely related to Sclerocactus but recent DNA research suggests it is closer to genera such as Ariocarpus! All the species occur in the western US. One species in particular, P. simpsonii, is quite possibly the most cold hardy of all cacti. Only a few species of Opuntia plus Escobaria vivipara can rival it in that regard. I distinctly remember as a child being on a trip to Rocky Mountain National Park in northern Colorado and seeing (what I now know to be) P. simpsonii growing among the rocks at over 10,000 feet in elevation. I thought someone had planted it and it was going to die over the winter as there are only a few months of year snow is not covering the ground there. Once I discovered it was native I was truly impressed with how tough a little cactus can be! Flowering and seed germination are best in cold regions.

Although I've been stressing how tough and cold resistant these cacti are, it shouldn't stop you from growing these attractive little guys. They will grow just fine in our climate and it is always nice to have some cacti from America in your collection. Especially ones from our most overlooked desert (from a cultivation standpoint), the Great Basin.
-- Kyle Williams
Photo in Cactus Chronicle:
 Pediocactus simpsonii

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Pelargonium - February 2018, January 2014, January-February 2009, February 2008, February 2007

On any street, anywhere in the country, you will find numerous homes growing Pelargonium hybrids in their flower beds. In cold weather regions they are annuals but in climates like ours they will live forever with good care. They are popular for their showy flowers that come in a vast array of colors too numerous to list. Most non-experts incorrectly call these plants Geranium. They aren't too far off as both belong to the family Geraniaceae, but true Geranium species are usually weeds. What few people realize is that there are a large group of true species Pelargonium (not hybrids) that are winter-growing succulents well suited for cultivation in California. These are the plants that our succulent of the month is focused upon. For purposes of our monthly show we also include the very closely related genus Sarcocaulon (aka Monsonia).

Pelargonium is a genus of approximately 200 species native to the African continent from South Africa to Kenya, even to Yemen. However, almost all the succulent species come from South Africa or Namibia, with the center of diversity being the Cape region. Pelargoniums are mostly winter growing succulents that are well suited for our wet-winter, dry-summer climate in California. During the growing season they have lush green leaves and attractive flowers, while during the summer time some look like dead sticks. The flowers aren't as gaudy as the horticultural hybrids, but any discerning grower will find them quite attractive.  

Most species are very easy to grow, if attention is paid to providing an environment very similar to their South African home. Some species, such as P. echinatum and P. triste are tolerant enough to be naturalized in the ground in Southern California when given good drainage and protected from summer watering. Many species will not go dormant if watered all summer, but the plant health and appearance both suffer. Like most cacti and succulents, when in doubt don't water! The potting mix for Pelargoniums should be well drained, with only small amounts of organic matter, if any. Fertilizer should be applied during good winter growing weather (i.e. not in the summer and not during cold, wet periods). A potting mix recommended by Michael Vassar is 50% pumice, 35% washed builders sand and 15% leaf mold based planter mix. Plants growing under these conditions will stay compact, have thick leaves, and a healthy appearance. A well grown Pelargonium will have leaves that appear to float near thick, rugged stems. If given too much water and fertilizer, they will grow leggy, and the leaves will become soft, large and droop. Plants grown hard will be healthier, and better able to survive hot summers undamaged. 

All Pelargoniums need pruning to maintain size and shape. Pinching new growth will make the plants bushy, and develop good trunk structure. Many are self fertile, and seed is easily collected after flowering. Most are promiscuous, and garden hybrids are easily set if more than one species is in flower at a time. Seed collected in the spring and planted in late September to November germinates quickly, and will have an entire winter to grow before going dormant during the summer.

Photos in the Cactus Chronicle - 
Pelargonium ferulaceum, Pelargonium carnosum, Flowers of Pelargonium carnosum 

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Pterodiscus caudiciform - July 2007

Pterodiscus, Sesamothamnus, and Uncarina are all members of the Pedaliaceae or Sesame family. They are all still relatively uncommon succulents, in spite of the relative ease of growing many of them.

Pterodiscus is a strictly African genus of relatively small caudiciform succulents. Although most of the collected species come from South Africa, Namibia and Botswana, the genus stretches through a good portion of central and eastern Africa. In habitat, the caudex is generally half above ground and half below. A single stem is produced every year. The stem produces non-succulent leaves and small, unusual flowers.

In cultivation, the nearly entire caudex is generally put above the soil line.

Photo in Cactus Chronicle:
Pterodiscus speciosus
-- Tom Glavich May 2005

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PLANT OF THE MONTH Library      page 4
serves as a reference library of descriptions of cactus and succulent plants 
designated as Plant-of-the-Month genera in the Cactus Chronicle newsletter. 

This section will grow as the web master adds information on past  and current POM selections.

  A   B   C   D   E   F   G   H   I   J   L   M   N   O   P   R   S   T   U   V   W   Y

Mammillaria - January 2012, February 2011, January 2008
  with colored (not white) spines - September 2018
  without hooked spines - April 2017, January 2014
  cluster - February 2015, March 2009
  with hooked spines - October 2016, January 2010

Mammillaria is one of the larger genera in the Cactus family, and one of the most variable, with some members remaining as solitary columns or globular for their entire lives while other develop into massive clusters over time. There is incredible variability in the genus with some species maintaining a small footprint ­ almost fingernail size. Other species grow into globular plants of substantial size. Mammillarias generate two types of spine; straight or hooked. It is important to note that all cacti start out as a single head and stay so for varying lengths of time depending on the conditions and growth patterns for a particular species.

Mammillaria is often one of the first cacti that a beginning grower buys. They are available, often for less than a dollar, at discount stores, and for just a bit more at local home centers and discount stores. A credit to the toughness of these plants, is that many survive for years in spite of all sorts of abuse and neglect. Many inexpensive purchases at local chain stores have grown on to be become show plants, the quality of the plant maturing with the skill and experience of the grower. In part because they are so generous with flowers and seeds, and the seeds germinate so readily, many rare species end up in unlikely places like home centers, supermarkets, and hardware stores. It’s worth keeping an eye out for unusual specimens, but beware of names found on discount store plants.

The secrets to good growth are a continual supply of water and fertilizer during the growing season (typically from March through October), strong light, intense heat if available, and maintenance of a clean and insect free growing environment. Many people starve and under water their plants, in attempt to avoid rot. Most Mammillaria will take quite a bit of water and fertilizer when in growth. During the summer heat growth slows for a time, picking up again when the weather cools, before stopping around Thanksgiving. Almost all Mammillaria will do just fine in Southern California, with little or no winter protection, as long as they are potted in a freely draining potting mix.

The appearance of white mealy bug egg cases (Mammillaria’s worst enemy) on the tips of the spines or the appearance of ants means that mealy bugs are sucking the sap and life of the plant. Immediate treatment is required, with a thorough washing, and spraying with an insecticide. A less toxic solution is to soak the entire plant in soapy water overnight, followed by a good rinse with water from a hose.

Mammillaria species differ radically. Some species produce hooked spines whiles other are either straight or feathery. Some species have hair or wool in the axils between the tubercles that provide protection against extreme sunlight.  Most Mammillarias originate in Mexico, although there are 10 species found in the south western portion of the United States. There are even a few species that extend as far north as Canada.

A distinguishing feature of all Mammillarias is that flowers appear at the point of two tubercles and form a ring around that particular stem of the plant. Flowers appear on the previous year's growth. A smooth brilliant red club­shaped berry appears if flowers are fertilized.

Photos in Cactus Chronicle:
Mammillaria bocasana, Mammillaria crucigera subsp. tlalocii,
Mammillaria gemnispina, Mammillaria perbella
J. Pilbeam, Mammillaria
David Hunt, The New Cactus Lexicon
Tom Glavich May 2003 
Edited by Steven Frieze, January 2012

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Matucana - July 2018, February 2013, October 2007

Matucana is a Peruvian cactus, found in the Western foothills and lower mountain slopes and valleys of the Andes. This plant is not as well known as many other South American cacti, even though they have wonderful body colors, spines and flowers.  Matucana grows fairly rapidly.  The general culture is similar to most other South American cacti. They need water when growing in the summer but need to be kept dry when cold. They do fine, unprotected in Southern California winters. 

Matucana can be quite variable in appearance, with some species being covered in dense long spines and others spineless or nearly so. Some are globular and others upright. Probably the most popular species is Matucana madisoniorum, a small attractive species with distinctive green skin, few spines, and interesting folds and ridges. One thing that adds to the popularity of this species is its passing resemblance to Lophophora or Peyote. Owing Lophophora is illegal (especially in California) while Matucana is not, so it can function as something of a substitute in people’s collections.

Matucana has posed taxonomic problems since its discovery. The genus Matucana was originally described by Britton and Rose in their book, The Cactaceae, published in 1922. The typical species is Matucana haynei, a plant known since the 1840s, under several different names. The genus is named after Matucana, the town near which the plant was originally found. In their original publication, Britton and Rose commented on the close resemblance of the flowers to Borzicactus, the size, shape, and color being the same. In 1960 Myron Kimnach moved the entire genus to Borzicactus.  Frederich Ritter re-segregated it in 1966, with the addition of some new species, which is the way it can be found in most recently printed references, picture collections and catalogs. There may be as many as 15 or 16 species, depending on the reference. Many of the species have a number of varieties, forms and cultivars, many of which are indistinguishable. Most of the species are very variable.
​-- Kyle Williams  

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Mediolobivia - May - June 2008, June 2007

research in progress

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Melocactus - August 2017, July 2010, August 2007

Melocactus, from Brazil, Mexico, Central America and the Caribbean, is one of the very first genera of Cacti described by Linnaeus in 1753. His work, Species Plantarum, is considered the official starting point of modern botany, specifically the botanical names of plants as we recognize them today. Although popular in cultivation, many of the species are endangered in the wild.

Melocactus has a very unusual growth habit that is nearly unique among cacti (only Discocactus is similar). When young the plant looks like a run of the mill globular green cactus. The kind of cactus you might not even give a second glace to in a nursery. However, after several years of growth a sudden, radical, change occurs and the cephalium is produced. The cephalium is a structure that produces in the wild nothing but flowers, fruit, and small spines. It has no chlorophyll and is smaller in diameter than the main body of the plant. Specifically, this  structure is formed on top of the main body of the plant. The body of the plant stops growing upwards and all growth for the rest of the plant’s life will be in the cephalium. This isn’t like Agave which dies after flowering. A cephalium will continue to grow and flower for decades with the plant as happy as can be. As mentioned above, one other genus of cactus produces a similar cephalium, Discocactus. Fortunately, the genera are fairly easy to tell apart as Discocactus have a flattened top and small cephalium with wool, plus large fragrant night blooming flowers. Melocactus are often larger, rounder, and can form a very tall cephalium. The cephalium produces tiny flowers and small spines but not copious wool.

Melocactus is from dry tropical regions and generally not true deserts. They thrive in hot humid climates where even the nights stay quite warm. However, they are fine in our Mediterranean climate with cool summer nights so long as we give them some extra warmth in the winter months. They can be grown outdoors here, but really prefer protection of night temperatures below 50F if possible. They like more moisture than similar looking non-tropical cacti, but don't keep them wet, especially in the winter.
-Kyle Williams
Photos in Cactus Chronicle:
A very old MelocactusMelocactus peruvianus, Juvenile Melocactus matanzanus

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Mesembryanthemaceae (Mesembs) - May 2014, June 2011

 Mesembryanthemaceae is one of the longest and ugliest plant family names. Thankfully, botanists don't call it that anymore. Now we refer to the family as the Aizoaceae. You can informally call them Mesembs as well. The change in name is due in part to the uniting of plants formally in different families. The Aizoaceae contains over 130 genera and nearly 2000 species, making it as big or bigger than the Cactaceae. Most Aizoaceae are fleshy and succulent plants. While most species that we grow are very highly succulent, such as Lithops, Faucaria, or Ice Plant (Carpobrotus), some genera are just slightly succulent and more resemble a typical herb.

Aizoaceae have a worldwide distribution in arid regions, including two species native to California. Despite the family technically being worldwide, the overwhelming number of genera and species (96%) come from southern Africa. It is interesting to compare the Cactaceae with the Aizoaceae in that both families have developed extreme succulence in order to survive their arid habitats, however how they went about it shows that evolution can converge on a basic idea in two different ways. Cacti have evolved thick fleshy stems that store water during lean times while also getting rid big green leaves (except in Pereskia and a few other species) that lose a lot of water on hot days. The leaves of a cactus have been turned into the spines that protect the plant from predators. The Aizoaceae took a different path. The stems have been nearly lost in many species (e.g. Lithops), or tend to be fairly thin and not much for water storage. The leaves have become extremely fleshy to the point where they are practically balloons filled with water. Whereas Cacti "fight" their predators by forming big sharp spines, the small stemless Aizoaceae hide from them by blending into their surroundings. They in essence become indistinguishable from rocks and are therefore ignored by thirsty predators. Another strategy employed by many Aizoaceae is to grow in the cracks of rocks. That gets them away from bigger, faster growing shrubs and grasses that would shade them out, but also helps them survive against predators. If a thirsty animal were to find one of these in the ground they could eat the whole thing killing it. If they find one wedged in a rock they might be able to eat the exposed leaves but the base of the plant would be protected, allowing the plant to regrow.

Our climate is great for growing most Mesembs, though, with nearly 2000 species, general advice for growing all of them is impossible to give. However, for the fleshy leaved South African species basic advice can be given. First of all, you need to know if your plant comes from the winter rainfall regions (which is very similar to our own climate) or from summer rainfall regions. For winter growers such as Conophytum, Cheiridopsis, or Fenestraria you can embrace our climate by letting the winter rains water them from fall through spring and then keeping them totally dry (or nearly so) during the summer. For summer growers like Faucaria, Pleiospilos, or Lithops relatives like Argyroderma and Tanquana keep them totally dry in the winter and water in the summer, except when it is very hot out at which time they should be kept dry again. With few exceptions no Mesemb wants to be wet for any length of time. So if our winters are especially rainy even the winter growers might need some protection. Similarly, don't soak your summer growers too often even during the growing season. Please realize that summer and winter growers may vary within a genus. For example, Titanopsis calcarea is a summer grower while T. hugoschlecteri is a winter grower. The plants don't care what genus they are, they care about the climate where they live in nature. When in doubt look it up! 

Photos in Cactus Chronicle:
Conophytum obcordellum, Fucaria tirgina 
-- Kyle Williams

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Miniatures - May 2018 & 2017 & 2016, October 2015, November 2014, September 2010

This month we aren't focusing on a specific genus or family of plants. Instead we will look at a growth form that everyone has space to grow, miniatures! It is important to note that because we are dealing with a descriptive term, not a botanical one, there is no hard and fast rule for what a miniature plant is. The closest we have is a pot size rule, which limits the maximum pot size to 3 inches diameter and requires the plants to be naturally small, not just a juvenile. For our meeting we'll be a little more relaxed and allow juvenile forms, within reason of course.

A miniature is not necessarily the same thing as a dwarf plant. For example, a number of Agave species are considered dwarf sized because they only get a couple feet in diameter. That is very small compared to a huge A. americana that can be 10 feet or more across, but isn't really what we mean by miniature. Another example would be a Bursera microphylla, the Elephant Tree, which can form a huge shrub or small tree. It is often grown as a caudiciform bonsai just a couple feet tall. That plant has been dwarfed but it still is not a miniature!

So what are some examples of true miniatures? Two great examples for cacti would be Copiapoa laui and Blossfeldia liliputana, the two smallest species in the family. They both form small clumps, but individual heads are usually 1⁄2" or less in diameter. Even slightly bigger species such as Ortegocactus macdougallii, Mammillaria theresae, or Puna clavaroides are ideal miniatures so long as the clump hasn't become too big.

While there are quite a number of miniature cacti, the number of miniature (non-cactus) succulents is even bigger. One of the best places to look for miniatures is among the mesembs. Some species of Conophytum are the very definition of miniature, in that some species such as C. pellucidum are so small that you could have upwards of 100 heads in a three inch pot! Many species of Lithops work well too. Also consider some of the mesembs that aren't living stones types such as Titanopsis or Aloinopsis species. Outside mesembs, consider some of the smallest Crassula, Haworthia, Sedum, or Avonia. These are just suggestions, but if you have a plant that looks good and proportional in a three inch or smaller pot then you have a miniature!

— Kyle Williams
 Photos in Cactus Chronicle —
 Blossfeldia liliputana, Conophytum pellucidum, Neohenricia sibbettii, Avonia alstonii ssp. quinaria

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Monadenium - October 2018, July 2007

The genus Monadenium is a close relative of Euphorbia. The key difference between the two genera is that Euphorbia flowers have four nectaries, while Monadenium have these fused into a single horseshoe-shaped nectary. This makes the flowers look significantly different, and most Monadenium flowers reflect this by generally having a distinct asymmetry not seen in Euphorbia. The name Monadenium reflects this fusion.

While Euphorbia is a world wide genus, Monadenium is confined to Africa, with a large part of the genus in tropical Africa. There are about 75 species, with many discovered recently, and more certainly to be found. Like Euphorbia, there is enormous size variation in the genus. There are leafy sub shrubs, true shrubs, and geophytes that have almost all their mass underground, with only deciduous leaves above ground when growth conditions are favorable.

As with most tropical genera, Monadenium are sensitive to temperature, and particularly to combined cold and wet. It pays to keep them dry during their winter dormancy, and to bring them out of dormancy with some care to keep the roots from rotting in the early spring.

Propagation of Monadenium is similar to Euphorbias. Cuttings can be from the stem succulent species. When they are fully dry, they will root and form typical plants. Cuttings of the geophytic plants are more difficult and many will not form typical caudexes from cuttings. Some require double cuts to form caudexes at all. (A double cut consists of an initial cutting, followed by removing the top of the rooted cutting when growth resumes.)

Photos in Cactus Chronicle:
Monadenium trinerve

H. Schwartz, The Euphorbia Journal
Sajeva and M. Costanzo, Succulents, The Illustrated Dictionary
Tom Glavich - March 2003

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Monotypic cacti - February 2010

Monotypic cacti or distinguished from other genera by the fact they have only one species per genus. This is not the case with most cacti and succulents where most genera have several species and/or subspecies associated with the genus.  

Monotypic cacti are endemic to their environments and are geographically more likely to be found in areas of Mexico, southern California, Arizona, New Mexico, and southwestern Texas.

One of the more remarkable instances of endemic monotypic cacti is in the Sonoran desert where Carnegiea gigantea forests (Saguaro) are found. Originating in the dry climate condition of the Sonoran Desert, these specimen dominate the landscape.

The following describes other monotypic cacti genera and the plants that comprise a more collective category of plants.

Leuchtenbergia principis is found in Mexico and is a specimen that looks more like an Agave than a cacti. The tubercles are approximately 3 to 4 inches in length and look much like agave leaves.  Flowers emerge from the tips of new tubercles in the spring.

Found in Southern Bolivia and northwestern Argentina, at higher elevations is Blossfeldia liliputana. This is a solitary or clumping miniature cactus that produces 1/2 inch stems or globular growths. This genus tolerates colder conditions than most cacti and require little or no water during the winter months.  

Obregonia denegrii is another monotypic cacti that is popularly known as the artichoke cactus. Found in Mexico Obregonia's can tolerate extreme cold for short periods of time. This is a solitary and globular plant that produces greyish green to dark green, triangular tubercles. A dome of white wool forms at the apex of the plant.

Ortegocactus macdougalli is endemic to Oaxaca Mexico and grows on limestone rock cropping at heights up to 6,000 feet.  Closely related to the genus Mammillaria, this plant is often grafted to avoid growing difficulties associated with its own root system. Another potential problem with Ortegocactus is the orange discolorations that frequently appear at the base of stems.

The last example of monotypical cacti presented in this article is Geohintonia mexicana.   Originating from the Nuevo León: Sierra Madre areas or Mexico, this plant grows on vertical cliffs filled with gypsum. Geohintonia are typically solitary plants with numerous ribs. Juvenile specimen are normally globose becoming more columnar as they mature. Plants are typically dark green covered by a glaucous pruina. Geohintonia spines are short, triangular, curved, and as they age brittle. This plant is endangered and is considered a prize specimen in a collection. Geohintonias are named for its discoverer George Hinton.

Photos in Cactus Chronicle:
Geohintonia mexicana, Ortegocactus macdougalli, Carnegiea gignatea forest,
Blossfeldia liliputana, 
D. Hunt, The New Cactus Lexicon;  C. Innes and C. Glass, Cacti
Steve Frieze, February 2010

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Monstrose - November 2018 & 2015 & 2013, February 2012, November 2011, October 2008, November 2007

​In monstrose plants, the mutations take place all over the plant.  Growth points originate all over the stem or branches causing very irregular growth.  The resulting plant may have little or no resemblance to its sister or brother in the same species.

see Crest and Monstrose   for more information

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