In lichens, the algal member belongs to the class Myxophyceae and the fungal member belongs to the class Ascomycetes. The algal member of the lichen is called the phycobiont or photobiont and the fungal member the mycobiont. In the coexistence of algae and fungi, fungi are more advantageous than algae. This position is called helotism as the algae live as slaves to the fungi. This symbiosis is called partial parasitism as the fungus collects nutrients by means of absorbents called haustoria. Some botanists have identified the position of fungi in lichens as controlled parasites on algae.