Long time ago I received it from Russia or Ukraina (probably Konstantin Pokhomov. He was my mentor in Bucephalandra and ferns. Those were good times
) and I did not think then about naming of this variety. I know that Dubius are broad and rather fluffy moss, but the name would indicate it that some Japanese collector had thus identified. We should have to get to the source. But i think this is one of the first Fissiden that appeared in aquariums coming from a collector who gave them that name. Today, many people are looking for Fissidens in the forest and trying to bring them under the water. I remember when I encouraged them to do so. And now we see the positive signs
I think that it acquired the right direction. Because we can look forward to interesting varieties of mosses in the aquarium.