Has anyone ever heard of "Ariocarpus w. var Caespitosa"? I have been trying to educate myself further on different cacti of interest, and I recently came across this name. I wasn't sure if it was a synonym for Lophophora williamsii, or if it was used in reference to a completely different species. I tried using the search function and I skimmed through the wiki, but to no avail. As far as I can tell, the picture I saw looked almost identical to L. wiliamsii, but I couldn't find any information on Ariocarpus Caespitosa elsewhere on the internet... Can anyone clear this up for me?

looks like it is a misnomer for lophophora.

Interesting. Thanks Parshvik!

At one point I do believe williamsii was in the genus ariocarpus

Here's a list of the names it's had in the past with the person who named it to the right,

Lophophora williamsii - (Lem. ex Salm-Dyck) J.M.Coult.
Anhalonium visnagra - K.Schum.
Anhalonium williamsii - (Salm-Dyck) Rümpler
Anhalonium williamsii - Lem. ex Förster
Ariocarpus williamsii - (Salm-Dyck) Voss
Echinocactus lewinii - (Henn. ex Lewin) K.Schum. in Engl. & Prantl
Echinocactus williamsii - Lem. ex Salm-Dyck
Echinocactus williamsii var. anhaloninicus - K.Schum.
Echinocactus williamsii var. pellotinicus - (K.Schum.) Rouhier
Mammillaria williamsii - (Lem.) J.M.Coult.

Wow, thanks hostilis!