Mammillaria (melanocentra)?

[mraroid]

Hi folks...

I am back again, hat in hand, asking for some help in IDing a cactus. I feel strongly that it is a Mammillaria.

The plant I have is about 5 and 1/2 inches (14 cm) in diameter. It is about 4 and 1/2 inches (11 cm) tall. The lighter purple buds are about 1.5 cm tall. The maximum amount of spines I see is about 7. The longest spine, on the side of the plant, usually points down and is about 1.5 cm long. Many primary spines as well as smaller spines both on the side of the plant and on the top have a dark brown to black tip. Tubercles are pyramid in shape. I have not seen any open flowers yet.

Anderson says that M. melanocentra is solitary. My mammillaria has a pup at its base. My plant is somewhat similar to the photograph (page 428) of M. polythele in Hunt.

This plant was bought by someone in a nursery in Ecuador at about 2000 m.

I am a Mammillaria dweeb. Out of my league. Any help appreciated.

Thanks

jack

mam1.jpg (51.88 KiB) Viewed 752 times

mam2.jpg (66.31 KiB) Viewed 752 times

mam3.jpg (72.04 KiB) Viewed 752 times

mam4.jpg (61.97 KiB) Viewed 752 times

mam5.jpg (63.15 KiB) Viewed 752 times

[vlani]

compressa or magnimamma

[mraroid]

Viana...

Thank you. I will look at them both. It flowered this afternoon. Enclosed are some photos....

jack

m8.jpg (62.49 KiB) Viewed 738 times

m9.jpg (61.31 KiB) Viewed 738 times

[mraroid]

Vlani and all....

I am always confused by Mammillarias. Some species appear to be chameleons to me - they can take so many different forms.

I looked into M. compressa. Anderson says it can grow to 3.9 inches in diameter. My specimen is at least 5 and 1/2 inches in diameter. Anderson also says M. magnimamma can grow to 4.7 inches in diameter. Perhaps we see more variation in size than Anderson says?

I am still not sure of anything. Any help appreciated.

Thanks

jack

[jfabiao]

Plant descriptions in books usually refer to habitat conditions. In cultivation plants will usually grow bigger, taller, greener, etc., being spoilt for water and nutrients.

[mraroid]

OK. I can see that jfabiao... Good point. I am still puzzled by this one. Any thoughts?

jack

[jfabiao]

As suggested above, M. compressa seems a good fit.

[mraroid]

Thanks jfabiao. I will dig into M. compressa.

jack