I tried this before several years ago but am not satisfied with the ID: Gymnocalycium reductum leeanum In particular, the flower images I've seen online are not much like those on my plant. The plant is small, still in a 4" pot after 9 years. These photos were already reduced to 400x400. I'm ha...

They are both Mammillaria. I think the one on the right (or is it top?) is Mammillaria pringlei, but can't see it well enough to be certain.

Maybe I missed something but I can't find anything that gives the actual size of the plant. We've been assuming it's small but how small is it?

Strongly resembles my C. forbesii monstrose ("Ming Thing").

It's been growing in a 6" (15 cm) pot in Southern California for nearly 7 years now. So I guess that makes it about 10 years old? Anyway, it's still only 9" (23 cm) tall and no sign of flowers.

If you look closely, you can barely make out some radials. They're just not showing up very well in the image.

The close-up reminds me a lot of my M. rhodantha, though its radials are hard to make out. Also a very large plant - now about 12 inches tall with two heads, each a little over 4 inches in diameter (not including the spines). Check out the sequence of images starting with this one: http://thumb8.web...

Does it look anything like this "peanut cactus"? http://thumb8.webshots.net/t/83/83/7/58/95/2561758950099935668hACscP_th.jpg It goes by several different names, including Echinopsis chamaecereus or Chamaecereus silvestrii. I'm not sure either is a proper name. The branches are typically le...

amanzed: I think yours is also P warasii. P leninghausii has lots more ribs and the growing point looks different (when you can see it).

I also have one that resembles #3. It was originally called Neoporteria multicolor when purchased in 2004. After searching Cactus websites I changed that ID to Eriosyce kunzei "multicolor". I think it's also considered to be a variety if E. senilis, as suggested by Tony.

Yup, there's so much variability within species that it makes the variability between species harder to pin down. Before you move on, take a look at this plant. It's the basis for my concinna ID:

#1 looks like Parodia concinna. It does resemble the images of P. werdermanniana on CactiGuide but I'd still go with P. concinna.

The last one looks like O. basilaris. It's native to some areas of nearby Southern California desert.

Yes -- I noticed that and I'm puzzled by the conflicting features. The growing point suggests P. concinna. It would be interesting to see what the flowers look like. If I can judge from my plants, concinna has the larger flowers with a definite red throat: http://thumb8.webshots.net/t/76/76/9/79/16/...

#1 - The spines make me think Parodia erubescens.

Oops! Just noticed I put in the wrong name when discussing the flowers. I meant to say that even the flowers seem to resemble my schumanniana more than the leninghausii. I'm so confused... :? I don't know what might effect spine length and suspect there is some variability. I should point out that I...