It is really a species. When you analyze a lot of plants of this species you will see no big variation how you can find it in natural hybrids, This was also the reason why we decided 1994 to describe it as a distinct species.
Here a picture of two different clones. One was in culture as richteri, the other as amazonica. But I found also some plants labeled as Phrag. peruvianum and other as topperi. all these names are tradenames and only Phrag. richteri was described officially.
Olaf is correct. Richteri is a species. Natural populations show not only stability, but the ability to reproduce. A natural hybrid origin for a species should not, and does not, relegate that species to perpetual hybrid status. Studies have shown that as much as 70% of flowering plant species have hybridization in their phylogenetic history.