algae

noun2

1. •
   Algal organisms viewed collectively or as a mass; algal growth.

   • Unlike seaweed, which grows in salt water, algae grows in freshwater ponds (chlorella or spirulina) or wild in the Pacific Northwest (Klamath blue green). — 2014
2. •
   A particular kind of alga.

   • This hollow, lumpy, yellow-brown algae grows epiphytically in sac-like clumps on large seaweeds and on rocks. — 1984