Mammillaria mystax

Mammillaria mystax after I bought it home on 9-21-18, #510-14.

Mammillaria mystax

mam-mil-AR-ee-uh  MY-staks

Synonyms of Mammillaria mystax (28) (Updated on 11-9-21 from Plants of the World Online): Cactus funkii (Scheidw.) Kuntze, Cactus leucotrichus (Scheidw.) Kuntze, Cactus maschalacanthus (Monv. ex Labour.) Kuntze, Cactus mutabilis (Scheidw.) Kuntze, Cactus mystax (Mart.) Kuntze, Cactus xanthotrichus (Scheidw.) Kuntze, Mammillaria atroflorens Backeb., Mammillaria autumnalis A.Dietr., Mammillaria casoi Bravo, Mammillaria crispiseta R.T.Craig, Mammillaria erythra Repp., Mammillaria funkii Scheidw., Mammillaria huajuapensis Bravo, Mammillaria leucocarpa Scheidw. ex Salm-Dyck, Mammillaria leucotricha Scheidw., Mammillaria maschalacantha var. leucotricha (Scheidw.) Monv. ex Labour., Mammillaria maschalacantha var. xanthotricha (Scheidw.) Monv. ex Labour., Mammillaria meschalacantha Salm-Dyck, Mammillaria mixtecensis Bravo, Mammillaria mutabilis Scheidw., Mammillaria mutabilis var. leucocarpa Schelle, Mammillaria mutabilis var. leucotricha Schelle, Mammillaria mutabilis var. xanthotricha (Scheidw.) Salm-Dyck, Mammillaria senkii C.F.Först., Mammillaria xanthotricha Scheidw., Mammillaria xanthotricha var. laevior Salm-Dyck, Neomammillaria mystax (Mart.) Britton & Rose

Mammillaria mystax Mart. is the accepted scientific name for this species. It was named and described by Carl (Karl) Friedrich Philipp von Martius in Hortus Regius Monacensis in 1829.

The genus, Mammillaria Haw., was named and described by Adrian Hardy Haworth in Synopsis Plantarum Succulentarum in 1812.

As of 11-9-21 when this page was last updated, Plants of the World Online by Kew lists 154 species in the Mammillaria genus. It is a member of the plant family Cactaceae with 146 genera. Those numbers could change as updates are made on POWO. The number of species in the genus and genera in the family fluctuates off and on.


Mammillaria mystax on 9-21-18, #510-15.

I bought this plant from Lowe’s on clearance on September 21, 2018. The Mammillaria mystax is another Owl’s Eye Cactus that divides dichotomically. The label says: 

“A globular cactus, usually solitary and growing to 6” height and sometimes to 8” in diameter. Spine color is highly variable with whitish wool and bristles at axils. Rings of reddish-violet flowers appear in April and May. Native of Oaxaca, Mexico. Protect from frost. Provide bright light/sun; hardy to 20° F. Water thoroughly when soil is dry.” 

The plant was growing in a 4 oz. (2 1/2” diameter x 2 1/4” tall) pot. The plant measured approximately 1 3/4” tall x 2 1/4” wide without the spines.

Mammillaria mystax from the top on 9-21-18, #510-16.

Mammillaria mystax is native to the highlands of south-central Mexico around Puebla, Guerrero, and Oaxaca at around 3,280-8,500 feet (1,000-2,600 meters) above sea level. It occurs in tropical dry deciduous forests and scrubland along with many other genera and species of cactus. 

Mammillaria mystax is a neat small cactus with very pronounced pyramid-shaped tubercles. In the wild, it produces very long, entangled spines on its crown but that seldom happens in cultivation. This species divides dichotomously as well as possibly producing offsets. It will produce a ring of rose flowers with brown mid-veins in up to 3 rows.

Mammillaria mystax on 10-10-18, #519-48.

I had to move the potted plants inside for the winter on October 10 because the forecast was calling for an “F” in a few days and the nighttime temperatures were getting cooler. I usually measure the cactus and succulents when I bring them inside, but I didn’t measure this one because I measured it when I brought it home in September.

Mammillaria mystax on 11-29-18, #535-22.

November 29 was a nice spring-like day, so I took the cactus to the back porch for a photoshoot. I was working on a post to show the difference between the cactus in my collection.

Mammillaria mystax close-up on 12-1-18, #535-17.

This close-up reveals many areoles with two central spines and up to six radial spines… In later photos, and upon taking a closer look, I could only find 4-5 radial spines and 1 central spine…


Mammillaria mystax on 6-22-19, #593-31.

Once evening temperatures warmed up enough I moved the potted plants back outside for the summer. The cactus were moved to the back porch to receive full sun.

I was fairly busy during the summer so I didn’t take as many photos as usual. Despite a little neglect, the plants all did very well.

Mammillaria mystax at 2 1/4″ tall x 2 1/2″ wide on 10-11-19, #639-67.

Next thing I knew I had to move the potted plants inside for the winter on October 11 because an “F” was in the forecast. I always take photos of all the plants as I move them inside and measure the cactus and some of the succulents. The Mammillaria mystax measured 2 1/4″ tall x 2 1/2″ wide (without the spines). It measured 1 3/4″ tall x 2 1/4″ wide when I brought it home on 9-21-18.

Mammillaria mystax from the top on 10-11-19, #639-68.

Mammillaria mystax has very prominent 4-6 angled pyramid-shaped tubercles, as many as 34 rows, lined in a spiral pattern. Areoles around the apex of the plant have a small amount of wool but appear to be absent on the rest of the areoles. The plant’s axils (the area between the tubercles) also has a small amount of wool and hair (depending on where you look).

Areoles produce 3-10 small white radial spines, some with dark tips. The central spines are a different story… Information states Mammillaria mystax can have 3-4 central spines, but sometimes they may have only one. They begin as a purplish-brown at the apex (top of the plant) but turn a grayish color (some with brown tips). With my plant, some of the smaller central spines below the midpoint are also brownish. For the most part, my plant has 4-5 radial spines and 1 central spine of varying lengths. I noticed many areoles with 2 central spines in earlier photos but they appear to have disappeared… 


Mammillaria mystax at 2 3/4″ tall x 2 3/4″ wide on 10-15-20, #747-73.

I had to bring the potted plants inside on October 15 in 2020 because an “F” was in the forecast’. As usual, I took photographs as I brought the plants inside. I always measure the cactus and some of the succulents. The Mammillaria mystax did very well over the summer and measured 2 3/4″ tall x 2 3/4″ wide at the time. That’s pretty good since it was 1 3/4″ tall x 2 1/4″ wide when I brought it home on September 21, 2018.

Mammillaria mystax from the top on 10-15-20, #747-74.

I always like looking at the top of the cactus. The above photo is a good example of how the central spines at the apex of the plant are purplish-brown and change color as the plant grows. The radial spines are a whitish color and much smaller than the central spines. Of course, the spines are very sharp…


Mammillaria mystax at 3 1/8″ tall x 3 1/4″ wide on 10-28-21, #853-19.

I didn’t have to move the potted plants inside for the winter until October 28 in 2021. There wasn’t a chance of “F” in the forecast until then which was quite unusual. The Mammillaria mystax did very well and grew to 3 1/8″ tall x 3 1/4″ wide.

Family: Cactaceae
Origin: South Central Mexico
Zones: USDA Zones 9a-11 (20-40° F)
Size: 6-12″ tall. Different websites have different information.
*Light: Sun to part shade
**Soil: Very well-draining. Potting soil amended with pumice or perlite and grit.
***Water: Regular watering during the summer and barely to none during the winter.

*During the summer, I keep most of my cactus on the back deck where they receive full sun. During the winter most cactus aren’t picky about the light because they are basically dormant. For several winters, mine were in front of the east-facing sliding door in the dining room so they didn’t get much light but they did great. I built a new shelf for the bedroom so now they are in front of a west-facing window. Most of the succulents are on a shelf in a south-facing window in a cool bedroom but a few are in my bedroom.

**When it comes to potting soil, finding the “sweet spot” is not exactly that easy when materials are limited. Cactus and succulent enthusiasts (and experts) do not recommend using peat-based commercial mixes but what choice is there for most of us. They say to use a loam-based mix… Hmmm… Our soil is loam, so do I just use dirt? Well, no because “dirt” is heavy and you need a “light” material. There is A LOT of cactus and succulent recipes online and some get pretty elaborate. Many say to use sand as an ingredient, but if you do that, it needs to be very coarse, like builders sand, because “ordinary” sand, like for sandboxes, is too fine and it clogs up the air space between the coarser ingredients. For MANY years I used 2 parts Miracle Grow or Schultz Potting amended with an additional 1 part of perlite and 1 part chicken grit. Schultz doesn’t seem to have as many large pieces of bark. Cactus and succulent enthusiasts recommended using pumice instead of perlite and grit so I checked it out… The “guy” at General Pumice (online) recommended using a 50/50 mix of potting soil and pumice. General Pumice has 3 different sizes to choose from depending on the size of the pot. SO, in 2018 I bought a bag of 1/8″ and mixed it 50/50 with Miracle Grow Potting Soil. I liked it pretty well. Then in 2020, since most of the cactus were in larger pots, I ordered the 1/4″ size. Pumice has a lot of benefits over perlite and has nutrients that are added to the soil when watering. Pumice is also heavier so it stays mixed in the soil instead of “floating” to the top. Still, there is the issue of the mix getting very hard once you stop watering the plants during the winter when you stop watering. I think this is because of the peat in the potting soil… SO, instead of re-potting the cactus and succulents in the spring, I started doing it during the fall and winter so their soil would be loose. Since you don’t water as frequently during the winter if at all, the timed-release fertilizer does not activate. I have not tried coir, but I am looking into it… 

I think a lot of growing tips online are written by people who never grew succulents and cactus. They just copy from one website and paste it to theirs. You have to sort of mimic the soil where species grow in their native habitat. For that, you almost have to go see for yourself… Typically, they grow in fairly rocky soil

***I water my cactus and succulents on a regular basis during the summer but barely ever in the winter (maybe a little in January) until close to time to take them back outside. 

You can read my Cactus Talk & Update and Cactus & Succulent Tips to get my opinion about growing cactus and succulents.

When you bring your new plants home from the store, you need to check their roots and the soil to see if they are wet. If so, you may want to re-pott it right away. It is advisable to re-pot them in a better potting soil more suitable for cactus and succulents.

The Mammillaria mystax is a great cactus and I enjoy having it as a companion. It is just weird it doesn’t have a common name. I will continue adding more photos and information as time goes by. Be sure to click on the link to Llifle below for further reading.

There isn’t a whole lot of information online about the Mammillaria mystax but hopefully, someday there will be more.

I hope you enjoyed this page and maybe found it useful. If you have any comments, questions, or suggestions, I would like to hear from you. Please click on “like” if you visited this page. It helps us bloggers stay motivated. 🙂 You can check out the links below for further reading. The links take you directly to the genus and species of this plant.


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