The groups of plants are pteridophytes (ferns), Bryophytes (mosses) and lichens.
Algae is not a good answer since they live in an aquatic environment.
Plants without flowers (ferns, mosses, lichens) have neither flowers nor seeds. They can colonize various environments, terrestrial or aquatic. Ferns and mosses for example settle between the stones of an old well. The reproduction of plants without flowers is mainly due to spores.