Home | E-mail | Plant files | Mail Sale Catalogue | Links | Information | Search

All the information and photos in cactus art files are now available also in the new the Enciclopedia of Cacti. We hope you find this new site informative and useful.


Mammillaria formosa CACTUS ART

Cultivation and Mail Sale
of Cacti and Succulents.

Mammillaria formosa
This Mammillaria gets only better looking with age. It will continue to put on more and more heads, as well as more white cotton topping.

Description: Plants solitary, sometimes clumping dichotomously with age (occasionally ramifies , producing a basal shoots) . Given enough time, M. Formosa will form mounds. Old plants with lots of branching are treasures. This plant variation is huge, the spine length, the wool covering and appearance varies from clone to clone.
Stem: Symmetrically globose at first, later cylindrical, with a depressed apex, 5 - 20 cm high, up to 10 (or more) cm in diameter. Light green,and may, with age, become rubberized at its base
Tubercles: Crowded, pyramidal, with latex, arranged in numerous, very close-set spirals. The Axil is woolly with white wool especially in the floriferous portion.
Areoles: Oval and woolly when young.
Roots: Fibrous.
Radial spine: 20 - 22, sometimes absent, thin, needle- or bristle-like, sometimes flattened, somewhat horizontal radiating and arranged laterally on each side of the tubercle, white, 3 - 6 mm long.
Central spine: 4 - 7, usually 6, pinkish to brown with darker tips, to 8 mm long.
Diurnal, funnel-form, dull white to light pink about 10 - 15 cm in diameter. Blooms adorn the crown of the plant, usually in a ring, in the growth of the previous year.
Blooming seson: Spring to summer.

Attractively deep dull pinkish-red coloured .Club-shaped.
Light brown.

M. formosa is a very variable species, and some of the different growing forms have for a long time been considered separate and distinguished subspecies, for example:

subsp. formosa: It has 20-22 radial spines and pink flowers. Origin: oahuila, Aguascalientes, Guanajuato, Zacatecas, Tamaulipas, Nuevo Leon and San Luis Potosi.
subsp. microthele: It has 22-24 bristly, flattened spines with white flowers. Origin: Cohahuila, Guanajuato, Tamaulipas and San Luis Potosi. This form should be grown conservatively to preserve the flat habit that is present in the wild.
subsp. pseudocrucigera: It has about 18 radial spines, (sometime lacking in mature areoles) the blooms are pink with paler margins. Origin: Queretaro, Guanajuato.

Mammillaria formosa has very teensie spines that lie flat against the plant so not that dangerous
(still can get you if not careful, though).

The white wool between the areoles makes this species a pleasure to look at and grow, but the diversity among individual specimens is considerable and the best plants have abundant white axillary wool. Hence, it is worth raising a batch of seedlings and selecting one or two that have the most wool.


Photo gallery: Alphabetical listing of Cactus and Succulent pictures published in this site.

Photo gallery MAMMILLARIA



Family: Cactaceae (Cactus Family) 

Scientific name: Mammillaria formosa ssp. formosa Galeotti ex Scheidw.
In: Bull. Acad. Sci. Brux. 5: 497 (1838)

Origin:  Mexico (Coahuila, Aguascalientes, Guanajuato, Zacatecas, Tamaulipas, Nuevo Leon and San Luis Potosi) Altitude 960 - 2.350 m.

Common Names include:  "Owl Eyes" and "Royal Cross"

Conservation status: Listed in CITES appendix 2.


  • Mammillaria microthele Muehlenpfordt
    Published in: Allg. Gartenz. 16:11 (1848)
  • Mammillaria formosa ssp. microthele (Muehlenpfordt) D.R.Hunt 1997
  • Mammillaria pseudocrucigera R.T.Craig 1945
  • Mammillaria formosa ssp. pseudocrucigera R.T.Craig (D.R.Hunt 1997)
  • Mammillaria arroyensis Reppenhagen 1989A

NOTE: At a first glance some forms of M. formosa may be confused with M. sempervivi, but it is not so difficult to distinguish, especially when in flower. M. sempervivi has very few radial spines and they soon drop off, leaving just 1 or 2 central spines. The flowers also are quite definitely yellow. Formosa and its various forms, usually have persistent radial spines, usually 2 to 6 central spines, and pale pink to white flowers. The only plant that differs in M. pseudocrucigera, often stated to be a form of sempervivi, but this has pink striped flowers, though its spines are more like the proper sempervivi. Pilbeam says that ssp. pseudocrucigera is the link between formosa and sempervivi.



This is one of the Mammillaria commonly called "Owl Eye Cactus", known for dichotomous branching (forking or dividing into two parts). Although dichotomous branching is not a common occurrence in cacti in general, it happens for some reason in this particular species.  What is interesting about this cactus is that it began as a single head, and it has now divided twice, forming what will be four separate branches. When the division process started, it was obvious that four heads would appear, but I dont think the one head divided quadruply. Most probably, one head became two, and then those two immediately divided.
Other Owl Eye Cactus among others comprise: M. karwnskiana, M. microthele, M. tlalocii and M. perbella.

Cultivation: It is easy to cultivate and make interesting specimens for any collection, and over time (in 12-15 years) it will form enormous colonies up to 50 cm or more in diameter!  It grows by dichotomously dividing, and also by producing offsets, and doesn't require any special treatment, except for the need for frequent transplanting, in order to manage its exuberance.  It needs as much light as possible without burning the plant, to keep the stems compact.  Provide a well-drained soil mix.  Water well and then allow to dry thoroughly before watering again during the growing season. It doesn't like much, if any, winter water, but can survive short exposures to freezing temperatures (-4 C.) if properly hardened off and kept dry.

Propagation: Mammillaria formosa is best propagated from seed.  Seed readily germinates at 20-22C, or by offsets if available.

Photo of conspecific taxa, varieties, forms and cultivars of  plants belonging to the Mammillaria formosa complex
(This Taxon has lots of synonyms ( like many other cacti) whit several controversial varieties and subspecies and comprises a multitude of different forms, but where each form is linked to others by populations of plants with intermediate characteristics):

Home | E-mail | Plant files | Mail Sale Catalogue | Links | Information | Search

All the information and photos in cactus art files are now available also in the new the Enciclopedia of Cacti. We hope you find this new site informative and useful.