Coryphantha cornifera is easy to confuse with coryphantha reduncicpina, the only different is flower, Cornifera have complete yellow flower, Reduncispina have yellow flower but red center.
This beautiful coryphantha is one of my seeds producer. the seeds that you are bidding on is by cross pollination with pollen of another coryphantha from my private collection, seeds were took this season, We have a lot of extremely rare cactus if you want something rare let me know and I will listing for you. Questions? feel free to email me.