lichen
/ˈlʌɪk(ə)n
/ /ˈlɪtʃ(ə)n /noun
1A simple slow-growing plant which typically forms a low crust-like, leaf-like, or branching growth on rocks, walls, and trees: the cedars are festooned with lichen [count noun]: rocks covered with gold lichens...
- A profusion of mosses, liverworts, lichens and ferns cover the woodland floor and festoon tree trunks and branches.
- There are a lot of mosses and lichens, simple in that respect, but it provides a habitat for such a range and complexity of wildlife that come ashore to breed.
- Although they seem barren, the flat rock outcrops, known as pavement rock, support some lichens and mosses.
Lichens are composite plants consisting of a fungus that contains photosynthetic algal cells. Their classification is based upon that of the fungal partner, which in most cases belongs to the subdivision Ascomycotina, and the algal partners are either green algae or cyanobacteria.
2 [mass noun, usually with modifier] A skin disease in which small, hard round lesions occur close together: patients with oral lichen planus...
- The white buccal lesions of oral lichen planus may necessitate biopsy to exclude leukoplakia, candidiasis, and secondary syphilis.
- The differential diagnosis includes psoriasis, lichen simplex chronicus, prurigo nodularis, and lichen planus.
- Other causes of genital dermatitis, such as lichen planus, can cause similar symptoms.
Derivatives
lichened
/ /ˈlɪtʃənd / adjectivesense 1. ...- This one, the First Master's favourite, its subtle pattern of gold and silvered scales congruent with the lichened rock, might yet find favour with his great-grandson.
- It could be ancient lichened tiles, but it isn't: it is made of steel, designed to rust naturally and durably, so never needing to be painted.
- Pipits cheeped on the lichened stones of the dyke.
lichenology
- It was awarded in recognition of his international contribution to lichenology, and in particular for his research into Polish lichens.
- But it does offer ‘an important basis for discussion, criticism and progress’ and will therefore appeal both to newcomers and to those currently working in the field of lichenology.
- Webpages devoted to lichenology are also maintained by members of the Association.
lichenous
sense 2.
Origin
Early 17th century: via Latin from Greek leikhēn.