Astrophytum myriostigma var. quadricostatum, is a unique and beautiful four-ribbed variety of the typically five-ribbed A.myriostigma AKA the Bishops Cap Cactus.
You will receive one bare-root seed-grown Astrophytum myriostigma var. quadricostatum of similar size to the ones photographed. Please see the third photo which includes an Australian $2 coin for size reference.
The fourth photo shows the mature form and is not for sale.