The ancestral green alga was a unicellular flagellate. The result of the primary endosymbiosis was a photosynthetic eukaryotic alga. It also describes a habit of coralline red alga. Like other lichens it is a symbiosis of a fungus and an alga. Spirulina which is an alga rich in proteins content has been commercially cultivated in India. "Cladophora" balls are formed from the filaments of the alga which are photosynthetic. Organisms which show approximate spherical symmetry include the freshwater green alga "Volvox". Those that endosymbiosed a green alga include the euglenids and chlorarachniophytes (= chloroplasts). Carrageenan, from the red alga "Chondrus crispus", is used as a stabilizer in milk products. Eggs of "A. maculatum" can have a symbiotic relationship with the green alga "Oophila amblystomatis". It is also found in "Spongiochloris spongiosa", a freshwater green alga. Efforts have also been undertaken with genetically modified alga in a bioreactor. A "stipe" is a stalk or stemlike structure present in an alga. A "holdfast" is a rootlike structure present at the base of the alga. The name "lamina" refers to that portion of a structurally differentiated alga that is flattened.