Peyssonnelia

Peyssonnelia is a genus of thalloid red alga comprising approximately 63 species. It includes the algae commonly known as rumoi-iwanokawa, mayoi-iwanokawa and akase-iwanokawa. Specimens can reach around 20 cm in size. "Peyssonnelia" produces tetraspores.
Segregate genera.
The genera "Cruoriella" and "Cruoriopsis" are sometimes considered to be part of "Peyssonnelia", but a 2007 dissertation by Krayesky separates them.
Species.
The species currently recognised are: