Unlabeled plant

Hi,
Here is an unlabelled plant, some folks in my club said M obscura, like pettersonii but more curved spines. They saw it 3 years ago when I got it, not recently, and w/o a fower. Is there a difference? Which is this? Here is 3 years ago

Here is now

THanks much, Mike

Dear Mike,
You will find that what a plant is named is dependant on which classification you follow. For myself I tend towards been a lumper although I should say I do not agreed with every thing David Hunt and John Pilbeam suggest.
Has for your plant., In Pilbeam's mammillaria book M.obscura is describled has being '' an untypified taxon, with no locality cited and probably referable to M.petterssonii. Craig allied it to M.wagneriana.''
Your 2nd picture certainly looks like my plants of M.pettersonii ML309, MK 176-49, LAU 1045 in both flower and spination and I would have no problem attaching that name to that plant.
Yours, Mark

Hello Mike,
I also think that it's pettersonii. I've an obscura in my collection, a young one (see picture). Hunt and Pilbeam have lots of names that they reject as untypified and not refound. In the mean while there were many fieldcollectors that have refound a lot of earlier described species. So, you could accept those refound plants or ignore them.
As you can see on the picture the spination is darker and shorter than on M. pettersonii
M. obscura SB 06

here's another pettersonii lookalike: M. huigerensis P 1756

I am sure that Mark and Hugo are right with their identification. I don't have an obscura myself, but in addition to plants that were named as pettersonii when I got them, I have plants which are pettersonii which were named as apozolensis, apozolensis v. saltensis, huigerensis, pilensis and hamilton-hoytia.
Are you still in touch with Woody Minnich? If so I'll pm you on a specific plant question as I have failed to find a valiud email for him to ask him directly.