Lithothamnion

Lithothamnion is a genus of thalloid red alga comprising 103 species. Its members are known by a number of common names. The monomerous, crustose thalli are composed of a single system of filaments which grow close to the underlying surface. "Lithothamnion" reproduces by means of multiporate conceptacles.
Species.
The valid species currently considered to belong to this genus are:
Uses.
The species "Lithothamnium calcareum" is, besides Tricalcium phosphate, often used as food fortification in plant-based milk substitutes to achieve a similar calcium content as a cow milk which is around 120 mg/100 ml.