However, lichens are ubiquitous and world wide, there are over 13,500 species. Lichens are a symbiotic composite of algal cells intertwined with fungal hyphae. The hyphae of the fungus provides moisture and the algal cells containing chlorophyll, provide nutrients. The algal cells must be magnified about 400 times to identify the algae. Lichen reproduction is somewhat confusing because it can take various forms which contain similar elements.
Fragmentation is certainly the easiest to comprehend.
After that, the lichen may produce spores, but only from the fungal element. The spores germinate and if successful, the hyphae engulf or trap the appropriate algal cell and thus begins a new lichen. Other reproductive mechanisms are isidia, small projections in the upper layer which contain both types of cells and soridia, which also contain both cell elements. A pothecia is a term for the fruiting bodies found on the surface of many lichens. Many lichens appear gray when dry, but a transformation occurs when wet.