Does anyone have this form of M. pringlei? Lau collected it on the 22/08/1981 on volcanic rocks that rise from the Valley at San Miguel el Alto, Jalisco, 1800m. He comments that it has short spimnes and differs from the normal taxons.
If you do have it, I'd love to see a photo, or better some seeds from the plant! It would help me to understand the scope of M. pringlei, which seems to be widespread in term sof collections, and with spine colours that range for light straw to deep yellow to brown (centrals).
I know that some (Hunt etc) lump this into rhodantha, which might be right of course. But there are differences in the original descriptions, both in spination and in fruit colour, although this is masked in later descriptions by some authors, as they describe the lumped rhodantha species and so incorporate all the variations found.
I'm not trying to invent the wheel, merely to try to understand better.