Mammillaria - January 2012, February 2011, January 2008
with black 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.
A 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
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
Mediolobivia - May - June 2008, June 2007
research in progress
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.
Photos in Cactus Chronicle:
A very old Melocactus, Melocactus peruvianus, Juvenile Melocactus matanzanus
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
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
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:
H. Schwartz, The Euphorbia Journal
Sajeva and M. Costanzo, Succulents, The Illustrated Dictionary
Tom Glavich - March 2003
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,
D. Hunt, The New Cactus Lexicon; C. Innes and C. Glass, Cacti
Steve Frieze, February 2010
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.