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Marine Animal Encyclopedia

Gray Lichen Pyrenocollema halodytes

Seen on hard, calcareous rocks, where it forms small, black-brown patches, gray lichen is unusual in being an association of three organisms—a fungus, a cyanobacteria, and an alga. The fungus anchors the gray lichen to the rock; the cyanobacteria and the alga contain chlorophyll and make food by photosynthesis. The cyanobacteria can also utilize nitrogen, a process that uses a lot of energy, and this comes from the sugar made during photosynthesis.

Gray Lichenzoom image
  • Phylum Ascomycota
  • Size Not recorded
  • Habitat Upper shore on rocks and on shells of some sedentary invertebrates
  • Distribution Temperate northeast and southwest Atlantic
Gray Lichen Habitat Mapzoom image