• Kelp, Diatoms, and Allies (Kingdom Chromista)

• Phylum Ochrophyta

• Brown Algae (Class Phaeophyceae)

• Order Ralfsiales

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Order Ralfsiales is an order of brown algae within the class Phaeophyceae, comprising mainly marine species that are typically crustose in form and occur on rocks, shells, and other hard substrates in intertidal and shallow subtidal habitats. Members of this order are characterized by their flattened, tightly adherent thalli, which often form brown, circular, or irregular crusts capable of withstanding strong wave action, desiccation, and other environmental stresses common in coastal environments.