Just looked up FO numbers in Ralph Martin's database. FO = Felipe Otero a Mexican cactus collector and the entry for FO 229 is:- Field number: FO 229 Collector: Felipe Otero Species: Mammillaria elegans v. Locality: Conpuerta, Sierra Mixteca, border Oaxaca-Pueblo, Mexico Altitude: Date: 14-May-88 No...

Or possibly a close relation of Mammillaria tlalocii = Mammillaria huitzilopotchlii since the central spines are usually produced on older plants, often intermittently or not at all.

Must have been about 30 to 40 years old as my plants don't grow very quickly. Alas it decided it had lived long enough and with no discernible change in growing conditions died two years ago. A species that does not show much visible signs if rotting since it does not go soft but you find out it is ...

I'm only a carpenter and amateur cactus grower not a chemist, but one of the best videos on "Cactus Anatomy" I came across was by Jackson Burkholder. It is in 6 parts but if you hang on as one part ends the other starts shortly afterwards.

https://www.youtube.com/watch?v=YKunfoYDHLI

I have used limestone chips, about quarter inch in size as a top dressing in the past, when I did not want to include them in the potting soil. These were obtained cheaply from a local builders merchant in the UK for spreading on bitumen felted roofs to keep the sun off and render them more fireproo...

Excellent researched post on the subject Oneday. =D> Inermis means unarmed or spineless, therefore subinermis means almost spineless or less spiny? Of course botanical names do not have to be appropriate and later often aren't, but usually are when the species was described. Britton and Rose picture...

Our plants have a tendency to spiral and all areoles are arranged in a spiral pattern. Seemingly the degree of stem spiralling depends on the concentration of auxins at the growing point. "So how do plants produce organs at regular intervals? Biologists knew the answer involved cells in the gro...

Pruning, akin to a near death experience, prompts plants to grow, flower and set seed in order to pass their genes on before they die! Pruning of most plants promotes new growth.

David Quail, a grower in cold old UK, raised dozens of these supposed slow growing cacti from seed and regularly sold them. You should even manage the very slow growing Aztekium ritteri and flower it by the time you are 60! He has just moved house and stopped selling I believe, but detailed his meth...

Possible, but hard to tell from the picture. The base does have some spines the top does not. Grafting on Lophophora is not likely since most grafts are done on Cerei or Echinopsis to speed up growth. Trichocereus being a favourite hardy stock.

Looks like it was originally hard grown then potted in a more nutritious soil and produced more vigorous new growth. However the new growth does not look etiolated being a nice dark green. If some plants have been grown slowly, in order to blur the old growth into more vigorous new growth, you have ...

C. haseltoniana usually has yellowish/orange wool in the crown or areoles. As said previously it is hard to identify Copiapoa's whilst small.

http://www.llifle.com/Encyclopedia/CACT ... seltoniana

Maybe somebody who grows many from seed can help?

The problem is Copiapoa's as young plants often look quite different to an older plant. http://www.llifle.com/Encyclopedia/CACTI/Family/Cactaceae/1380/Copiapoa_cinerea#:~:text=Description%3A%20Copiapoa%20cinerea%20is%20one%20of%20the%20most,solitary%2C%20or%20slowly%20offsetting%2C%20globular%20to%2...

See:-

https://cactus-moravia.eu/other-news/py ... ak-sp-nov/

Some tuberous rooted cacti that grow among or under rocks or even shrubs have ev0lved an extreme form of etiolation to get their flowering heads above rocks etc for pollination. This modification is retained even if grown in pots when no rocks are present. https://bcss.org.uk/turbinicarpus-subterran...