Genital lichen planus, which may cause lesions on the glans penis or skin of the scrotom in males, and the vulva or vagina in females. Symptoms may include lower urinary tract symptoms associated with stenosis of the urethra, painful sexual intercourse, and itching.
https://en.wikipedia.org/wiki/Lichen_planus
Much of the rest of the website consists of expansions of the topics presented here and you can get to many of those expansions by clicking on the embedded links. A lichen is not a single organism. Rather, it is a symbiosis between different organisms - a fungus and an alga or cyanobacterium. Cyanobacteria are sometimes still referred to as 'blue-green algae', though they are quite distinct from the algae. The non-fungal partner contains chlorophyll and is called the photobiont.
https://www.anbg.gov.au/lichen/what-is-lichen.html
Although lichen planus can present with a variety of lesions, the most common presentation is as a well-defined area of purple-coloured, itchy, flat-topped papules with interspersed lacy white lines (Wickham's striae).
https://en.wikipedia.org/wiki/Lichen_planus
Lichens show a variety of growth forms and there are terms used to name these forms. The following are three very commonly seen types: Fruticose lichens are erect or pendulous and markedly three-dimensional. The genus Usnea (right) is an example.
https://www.anbg.gov.au/lichen/what-is-lichen.html
Interestingly, the same alga can combine with different fungi to produce entirely different lichens. The same fungus can also form different lichens depending on the type of alga which it associates with. Most lichens contain only one kind of alga, but some may contain two.
http://www.countrysideinfo.co.uk/fungi/lichens.htm
Lichen planus (LP) is a chronic inflammatory disease of the skin, mucous membranes and nails. Lichen planus lesions are so called because of their lichen-like appearance and can be classified by the site they involve, or by their morphology.
https://en.wikipedia.org/wiki/Lichen_planus
While most lichen partnerships consist of one mycobiont and one photobiont, that's not universal for there are lichens with more than one photobiont partner. When looked at microscopically, the fungal partner is seen to be composed of filamentous cells and each such filament is called a hypha.
https://www.anbg.gov.au/lichen/what-is-lichen.html
Lichens present a very intriguing problem for people whose job is to name different kinds of organisms. This is because a lichen is not a separate organism in the sense of being one type of individual. It is actually a close partnership between a fungus and an alga. (Algae are very simple plants). The two types of organisms in the partnership are so closely interwoven that they appear as a single individual. This individual looks entirely different to either of the partner organisms making up the structure. Lichens are distinctive and they form many different, recognizable types. Many of these have been given specific names of their own, despite the fact that each lichen is already a mixture of different species. There are more than 1,700 species of lichen in Britain.
http://www.countrysideinfo.co.uk/fungi/lichens.htm
The term lichenoid reaction (or lichenoid lesion) refers to a lesion of similar or identical histopathologic and clinical appearance to lichen planus (i.e. an area which looks the same as lichen planus, both to the naked eye and under a microscope).
https://en.wikipedia.org/wiki/Lichen_planus
Oral lichen planus (also termed oral mucosal lichen planus), is a form of mucosal lichen planus, where lichen planus involves the oral mucosa, the lining of the mouth. This may occur in combination with other variants of lichen planus.
https://en.wikipedia.org/wiki/Lichen_planus
different types of lichen
Fruticose lichens is a type of lichen, Fruticose lichen is a type of lichen.