How could we tell if alga is a member of the rhodophyta or the phaeophyta if it is both red and brown?

To determine if an alga is a member of the Rhodophyta (red algae) or Phaeophyta (brown algae), we can analyze its pigment composition and cellular structure. Rhodophyta typically contains phycoerythrin, giving it a red color, along with chlorophyll a and other accessory pigments, while Phaeophyta primarily has fucoxanthin, contributing to its brown color. Additionally, examining the alga's morphology and reproductive structures can provide further insights, as each group has distinct features. If the alga exhibits characteristics typical of both groups, genetic analysis could definitively clarify its classification.