homotypic synonym, validly published under the ICN (Botanical Code), distinct rank
Notes:
❗ Phormidiummucosum var. arvense is the correct name instead if this variety is regarded as a separate variety (i.e., if its nomenclatural type is not assigned to another variety whose name is validly published, legitimate and not rejected and has priority) within a separate species Phormidiummucosum within a separate genus Phormidium.