Algae belongs to the group
Thallophyta
Thallophyta is the most primitive and simplest members of the plant kingdom. The plant body is not differentiated into root, stem, and leaves. All algae are thallophytes. Bryophytes (Mosses, liverworts and hornworts) are non-vascular, so they do not have the right types of tissues to develop roots, stems, or leaves. Gymnosperms are vascular plants with distinct shoots and roots. They do not produce flowers and fruits. Pteridophyta (ferns) also have vascular tissues and distinct roots, stems, and leaves.