homotypic synonym, validly published under the ICN (Botanical Code)
Notes:
🧍 Later isonym of Oscillatoria princeps f. purpurea Collins 1900.Publication:
Collins FS. Oscillatoria princeps forma purpurea Collins. In: Collins FS, Holden I, Setchell WA (eds), Phycotheca boreali-americana. A collection of dried specimens of the algae of North America 1900. Fascicle XVI, Nos. 751–800, Unknown Publisher, Malden, Massachusetts, 1900, p. 753.