They differ from other coralline algae such as Corallineaceae via their reproductive structures, which are confined to nemathecia - external pustules which form from the surface cells.

[7] However, a study in 2018 found that while CO3 concentrations of Peyssonnelia squamaria decreased after exposure to elevated CO2 levels, the photosynthetic performance actually increased, suggesting that the species has the capacity for self-regulation under acidic conditions, and may benefit from a more acidified ocean.

[9] Information on the life cycle of Peyssonnelia is limited, however, based on culture studies, tetraspores grow into discs and can reach up to 300 um in 10 days.

[10] A study in 2009 found that extracts of a certain Peyssonnelia species contained peyssonoic acids A-B (1-2), which are growth inhibitors for bacteria (Pseudoalteromonas bacteriolytica) and fungal pathogens (Lindra thalassiae) of marine algae, as evidenced by strong antimicrobial activities in the ecological assays.

inhibited another fungal pathogen, Dendryphiella salina, but not through peyssonoic acids A-B (1-2), suggesting it has other secondary metabolites to defend against the fungus which remain unexplored.

Peyssonoic acids A-B (1-2) were also tested for inhibition of human ovarian cancer cell lines, with 2 showing higher inhibitory activity than 1.