A.F.A.I.K. Red Reishi (RR) and "Reishi" are very often used interchangeably about same Ganoderma Lucidum muhroom. It is also called "Lingzhi" in Chinse medicine.
The majority of Reishi on market is the red variant, a.k.a. RR. Therefore, whenever you buy "Reishi", it is most often RR. And if it is named G. Lucidum or Lingzi, it is RR (except, of course, if the seller is dishonest).
In practice the only other color of Reishi which you might find on market is black Reishi. However it is pretty rare. All other color variants are super rare.
The majority of Reishi on market is the red variant, a.k.a. RR. Therefore, whenever you buy "Reishi", it is most often RR. And if it is named G. Lucidum or Lingzi, it is RR (except, of course, if the seller is dishonest).
In practice the only other color of Reishi which you might find on market is black Reishi. However it is pretty rare. All other color variants are super rare.