alga

noun (usually in plural algae /-jē/)

• a simple nonflowering plant of a large group that includes the seaweeds and many single-celled forms. Algae contain chlorophyll but lack true stems, roots, leaves, and vascular tissue.

  • Divisions Chlorophyta ( green algae), Heterokontophyta ( brown algae), and Rhodophyta ( red algae); some (or all) are frequently placed in the kingdom Protista. See also blue-green algae