The fungal part of the organism nearly always consists of a number of the Discomycetes or Pyrenomycetes, while the algal portion is a member of the Schizophyceae (Cyanophyceae or Blue-green Algae) or of the Green Algae; only in a very few cases is the fungus a member of the Basidiomycetes.
Glycogen, a substance related to starch and sugar, is found in the Fungi and Cyanophyceae as a food reserve.
In the Cyanophyceae the contents of the cell are differentiated into a central colorless region, and a peripheral layer containing the chlorophyll and other coloring matters together with granules of a reserve substance called cyanophycin.
X.; The Cell Structure of the Cyanophyceae, Proc. Roy.
The foreign algae are always members of the Cyanophyceae and on the same individual and even in the same cephalodium more than one type of gonidium may be found.