Ricordea and yuma are technically the same things; i.e. all yumas are Ricordeas, but not all Ricordea's are yuma.
Ricordea is a genus of corallimorpharians, what we refer to here as Mushrooms. Yuma, is a species of Ricordea. Florida, is another species of Ricordea.
The most distinguishable feature between the two, IMO, are the "bubbles" that form around the mouth of R. yuma but are not present around the mouth of R. florida.