Identification: Some Cacti That Have Me Stumped. Help!

My guess on the first one is that it could be Eriosyce bulbocalyx or something similar in the genus or something from a similar genus. Looks like there's 14 ribs. Usually 6 radial spines. 2 in the center. chalky white spines, reddish brown tips. Turning in/up. spines are thick.

The second. My guess is Coryphantha palmera/salm-dyckiana/palmeri. Or maybe it is something else. who knows. 17 radial spines. straight as an arrow very pale yellow, almost white with black tips. 2 strong horn-like central spines, little bit of yellow near the tubercle with a small strip of red before a majority of the spine is black.

The third I'm pretty sure is Gymnocalycium bruchii or some variety of it. but I could be wrong. it has two small pups growing off of the body. Cylindrical in shape. Eight very symmetrical ribs. Distinctive tubercles now but maybe just because it is dehydrating. 11,12,13 white-ish radial spines very soft and flexible.

The fourth. My guess is it could be a gymnocalycium schickendatzii. Not sure, it is very small so I don't know what to compare it to. maybe I just need to let it grow to find out?

The last. the closest I could find a relative to was Mammillaria phitauiana or M. fraileana? 8 radial spines. 1 long hooked central spine, very thin.

Thank you so much for any help you can give me.

Season's Greetings.

 

I have never been good at identifying cacti from photos and these were not easy (especially without flowers), but I have some comments. Question: where did you find those names? Preston-Mafham? They are somewhat old-fashioned. Counting ribs is not a reliable way to identify cacti btw., the difference between wild and cultivated, young and old plants can be large.
Where did you get them? If they are mass-produced plants it almost rules out some species that are slow and/or difficult to grow.
1. Have you considered Denmoza?
2. Agree with Coryphantha, but it is a young plant, it might not have developed the characteristic features yet. I can hardly see any grooves, for example. There is no species called palmera. C. palmeri Britton & Rose should have at most 1 central spine, usually hooked. Identifying Coryphantha can be challenging, many species look similar and the spination is variable. In my eyes it could for example be the relatively common cornifera, which has a very variable spination.
3. Yes, probably bruchii.
4. Could be Gymnocalycium, but it does not look like schickendantzii. As you suggested, this one is probably too young to identify.
5. Looks like a Mammillaria, but I am not convinced that it belongs to either of the two suggested species. But there are so many Mammillaria and I don't know them well.

 

To try to identify these plants, I go to a few different books that I have found at my local library. They are somewhat out of date, but once I find a plant, I try to find what the name of the plant is online. I like using cactus-art.biz because the pictures are of plants in cultivation in pots, so they are more comparable to my plants than from some other sites I have been on. I mean to buy a one-year membership to an arboretum nearby that has a library with a large collection of plant books in it. The cactus section isn't meager, so I believe that will benefit my understanding of all of these plants.
Where do you go to find information on cacti?

These were all mass-produced plants, yes, so I do understand your thought on that.

The *C. palmera* was supposed to be C. cornifera. ha. my mistake. Must have not been paying good attention.

Thank you for all your help.

 

Just keep in mind that the Internet is full of pictures of misidentified plants ...

Cactus Art's photo gallery is good, as is the one at CactiGuide. Some of the bigger nurseries have good photos, but they are often focusing on the flowers.

I have a small cactus book collection that I use a lot. Some general books, some covering a single genus. Few of them are organised in a way suitable for identification by visual comparison though. The closest is probably the "Atlas" part of The New Cactus Lexicon, which contains only pictures ordered in a useful way. Much of the older literature (and some more recent books too) can be downloaded (legally) from this site. A lot has happened since they were published, but they have often helped me to sort things out.

One of the best ways to get a decent guess is to ask at one of the dedicated cactus forum, such as BCSS, CactiGuide or The Garden Forums where some members have grown hundreds of plants from a particular genus and knows about those small differences that are difficult to express verbally. (There are of course also some people who has no idea of what they are writing about but want to make themselves heard, but they are hopefully corrected by someone more experienced).

 

Ha. All very useful to hear. The website with all the downloadable books is going to be great. And I'll have to get onto those other forums. Thanks very much.