Opuntia Blog

Dracaena cinnabara tree, image from Wikipedia, click on the image to see the original (large) image at Wikipedia

Dracaena cinnabari is not a cactus, but it is an amazing plant. D. cinnabari is endemic to Socotra Island in Yemen. Its common name, dragon blood tree, derives from the reddish sap obtained from the tree that is used as a dye or a medicine. Wikipedia reports that the red resin was used in dying wool, gluing pottery, as a breath freshener and as a lipstick. Purportedly, the red sap has been employed in magic rituals.

Some sources suggest that D. cinnabari was widely distributed over Socotra Island in the past, but while it is still widespread, it is in scattered populations. It is not clear why overall numbers of the tree have declined because Socotra Island is not yet subject to typical ecological pressures (eg, urbanization, ranching). The trees typicall grow “areas affected by the mists, low cloud and, in particular, the constant drizzle of the monsoon.” Perhaps such areas are not as common as in the past? One source reports that there is circumstantial evidence of drying in the region over the past few hundred years.

You can find out more about D. cinabari at the Arkive. 

Ariocarpus fissuratus, photo by Craig Howe

Parts of Texas are home to Ariocarpus fissuratus, a plant wonderfully adapted to harsh conditions. Its gray-green (or brownish) color help it hide among rocks where it grows (typically in calcareous soils). Much of the plant is, in fact, underground as a subterranean storage organ–a factor that also helps Ariocarpus to hide.

Ariocarpus has been placed in various genera over the years, including:  Mammillaria, Anhalonium, and Roseocactus.  You can read more about A. fissuratus here and here.

Aztekium hintonii

There are just two species of Aztekium, A. hintonii and A. ritteri. They are small, globular plants with pink or white-pink flowers. The two species grow on gypsum cliffs in Mexico and are quite limited in natural occurrence. Each species is known from its own (single) location in the state of Nuevo Leon.

Boedeker reported A. ritteri in 1928 and it was over 62 years later that A. hintonii was reported. Both plants are fairly small, and with limited occurrence. It is understandable that they were not discovered early in cactus discoveries.

You can read more about Aztekum here and here.

Lophophora

It is confusing to sort out Lophophora names; some authorities suggest there is really only one species, whereas others indicate there are four. Of course, the various putative species have have been named more than once.

The plants are small and slow growing, taking 20 years or more to reach adult size (about a small tangerine) in the wild. L. williamsii is the famous member of the group because it naturally contains mescaline–a mind altering hallucinogen. L. williamsii is well known as “peyote.”

Peyote plants are hunted by people and resold because of their hallucinogenic properties, and several sources report they are in danger of extinction in the wild. However, a simple Internet search suggests that there are multiple seed vendors around the world.

Lophophora might be an easy plant to grow (I’m without first-hand experience) because it comes from south Texas and north Mexico, in an area with sweltering hot summers and way-too-much winter rain (and sometimes summer rain). Cacti from this region, that I have grown, are flexible in their requirements; they are not so cranky as plants from drier (ie, more westerly) areas.

You can learn more about Lophophora here or here.

Opuntia species can be pests in grazing lands. Sometimes the plants become very numerous and crowd out desirable forbs and grasses. Controls for weedy Opuntia are various but are often ineffective. One strategy to control Opuntia is a prescribed extreme burn; the use of limited (but hot) grass fires to destroy Opuntia species.

One study reports,

“A central prediction of our research is that extreme fires will serve as an economically and ecologically preferable management tool for controlling problematic Opuntia populations…”

Opuntia lindheimeri in experimental burn plot near Sonora, Texas, fire damage visible in background, photo by Bill Rogers

Sample graft from article

The World Wildlife Fund has prepared an interesting article that you can read here. It is concerned with “Trade and Conservation of Chihuahuan Desert Cacti. The article describes plants in Texas, New Mexico, Arizona, and Mexico that are vulnerable to overharvesting. Even Opuntia are vulnerable because they are harvested unsustainably for use in cosmetics.

Most of us, as cactus growers, only grow seed-grown plants from reliable dealers, but a blackmarket trade continues across international and state borders.

“World Wildlife Fund (WWF) considers the Chihuahuan Desert Ecoregion (CDE) of Mexico and the United States an important ecoregion for conservation because of its outstanding biological diversity, ecological fragility, and environmental concerns. The ecoregion, rich in natural resources, faces a range of visible threats stemming from human activities such as mining, fossil fuel exploration, livestock grazing, industrial agriculture, and development.”

Astrophytum asterius, 'Super Kabuto'

There are four species of Astrophytum; one of the most common is Bishop’s Cap (A. myriostigma). Another species common in cultivation is A. asterias.

Astrophytum asterias is a spotted species from Texas and Mexico (the Chihuahuan Desert) that resembles a sea urchin or sand dollar in 3D shape. A. asteras has given rise to some mutants. In some of the mutants the spots are enlarged and dramatic.

One spotted A. asterias mutant is ‘Super Kabuto.’ I’ve tried to understand what the spots are (are they regions where chlorophyll is just lacking, or regions of lenticels?), but I can’t figure out what the spots are. In the photo it is easy to see how the areoles (fuzzy) differ from the spots.

You can learn more about Astrophytum here and here. You can buy Astrophytum seeds at Mesa Garden Nursery.

Astrophytum myriostigma

Puna bonnieae, photo by Willy Smith, click image to go to Willy's Cactus Argentina Web site

Puna bonnieae was discovered by Dave Ferguson and his colleagues in Catamarca, Argentina nearly 20 years ago. It is a beautiful small plant that looks a bit like an immature Tephrocactus geometricus. At least one author has proposed reassigning Puna bonnieae to Tephrocactus. For me, it will always be an Opuntia; sentimentally I think of all the opuntiads as types of Opuntia though such opinion is not encouraged by DNA data.

P. bonnieae has a nice pink flower that is startling in some photos because the plant is seems nonexistent, buried as it sometimes seems. Like some other opuntiads, P. bonnieae has underground storage organ, a turnip-like appendage that must help it survive really cold weather or really dry weather.

You can read more about P. bonnieae here, and here.

Brachycereus nesioticus, Galapagos Islands

Brachycereus nesioticus grows in lava fields on one or more of the Galapagos islands (hence the name “lava cactus”). B. nesioticus grows in lava where (almost) no other plant will grow, often right near the ocean, but inland also. Because it grows on nearly naked lava, B. nesioticus is one of the first plants to colonize lava fields.

The species has a furry look because of the dense spination, and grows in clumps up to 1- or 2-foot-tall (the name Brachycereus means “short cereus”). The stems are golden or yellow in youth, but darken to gray or black as they mature and the spines age. The white flowers open in the morning but close early–I don’t know what the pollinator is but presume it is an insect or a bird. Possibly the fruits are eaten by iguanas.

More pictures (including the frilly white blooms) can be found at the CactiGuide.

There are more species of cacti in the Big Bend region than any other location in the USA; over 5 dozen species of cacti are found in the area. The large numbers of cacti (and other desert plants) are due to the many habitats, soils, and elevations that are found in the park as well as its location in the northern Chihuahuan Desert (with influences from the Rocky Mountians, the Edwards Plateau, and the Sierra Madre Mountains).

A number of Opuntia species are found in the greater Big Bend region (or in the National Park itself) and nowhere else in the USA. These include O. rufida, O. chisosensis, and O. spinosibacca.

You can find more images of Big Bend here.

Sclerocactus wrightiae is an endangered species, listed in 1979 by the US Fish and Wildlife Service. It grows in a few counties in Utah, and nowhere else. Another name for the cactus is “fish hook” cactus, a name it richly deserves.  

 The plant is typically small, less than six  inches tall, and has white, yellow, or pink flowers. The species may exhibit variation from location to location (eg, flower color), perhaps due to introgression with other sclerocacti.

S. wrightiae  can be found in pinon juniper woodlands at 4,200 ft. to nearly 6,000 ft, often in association with grasses and Opuntia polyacantha. Typically, the plants are growing in very exposed (windy, sunny) locations and in alkaline soils.

Sclerocactus wrightiae, image from State of Utah Natural Resources

One scientific paper from 2005 (Martinez-Avalos and Jurado) describes the situation of cacti in Tamaulipas, Mexico. Of about 170 cactus species identified, nearly one-third (29%) are considered endangered.

“An inventory of the species of Cactaceae from Tamaulipas, Mexico was carried out. The study area was divided into 48 squares of 30 min of latitude and 30 min of longitude… Species diversity per squares and their geographic distribution range were obtained. Results showed a diversity of 120 species and 53 subspecies, of total 49 are considered as endangered…”

The interesting thing is that collections were necessarily limited, ie, no one can cover every square inch of Mexico and adjacent Texas. So, spot sampling is employed with the hope that nothing important is missed. The good news is that areas of high diversity were identified for protection.

“Collections were made at 60 sampling sites distributed over an area extending in to the bordering states of San Luis Potosi, Nuevo Leon, Veracruz and Texas (USA)…The genera most represented were Mammillaria, Coryphantha, Echinocereus and Opuntia.”

The surveys (such as Martinez-Avalos and Jurado conducted) are important. There is no other way that we can know what plants exist and “how they are doing.” It is unfortunate that that such surveys are not common enough and that they were not widely conducted in previous years. Who know what plants we have already lost to science.

Mammillaria (wrightii?), Las Cruces, NM and into Mexico

Some of the rarest plants in the world are opuntiads. One paper from about 10 years ago reported one of the stumbling blocks that Opuntia spinosissima (= Consolea spinosissima)  faces.

“Opuntia spinosissima (Martyn) Mill. (Cactaceae) is an extremely rare taxon with a single remaining wild population of 13 plants located on Little Torch Key, Florida. The plants rarely set viable seeds…I hypothesize that O. spinosissima is a sterile polyploid and that the 13 extant plants are asexually derived from a single lineage.”

This is terrible news. Essentially, after reporting her studies and findings (abstract), the author (Dr. Negron-Ortiz) concluded that all of the plants at the remaining location (in the wild) are really the same plant (ie, they are all derived from rooted bits). The author concluded that all of the plants are self-incompatible (they don’t accept each other’s pollen); if any seeds are produced they are identical to the parent plant, and thus, identical to all of the plants. Lack of genetic diversity is a real problem that seems to cause sterility in this case.

Opuntia spinosissima, photo from www.plantsystematics.org

Opuntia multigeniculata, northern Arizona

Opuntia multigeniculata has been variously described as a stable species, a hybrid between O. whipplei and O. echinocarpa, or even as a variety of O. whipplei. I think the general consensus now is that it is a stable species that is found  infrequently, but regularly, in southern Nevada and northwestern Arizona. The common name is the blue diamond cholla, perhaps in reference to Blue Diamond Rd. south of Las Vegas (just a guess).

There is good Web coverage for such an uncommon Opuntia; the State of Nevada has published a monograph about O. multigeniculata; one Web site (Vegetation Around Las Vegas) provides nice habitat photos; and an environmental report is available.

Opuntia multigeniculata is an uncommon cylindropuntia that occurs in sporadic areas of the Mojave Desert, up to 4,000 or 5,000 ft. As such, it should easily survive temperatures to zero F (-18 C). It might be able to withstand even colder temperatures. The problem for hobbyists is that the plant is apparently not in commerce.