Are they the same species?
I bought these two cactus from a home improvement store. The one in small pot on the right has a tag. It is a Pseudo epostoa melanostele. But the one in big pot on the left has no tag. I wonder they are the same species. The one in small pot seems to have fuller hairs than the other one.
I hope someone can help me to identify the one in big pot. Thanks in advance.