[a. L. līchēn, ad. Gr. λειχήν in all the senses below. Cf. F. lichen, Sp. liquen, It. lichene.]
† 1. = LIVERWORT; the lichens and liverworts having formerly been included in the same group.
1601. Holland, Pliny, II. 245. Another kind of Lichen or Liuerwort there is, cleauing wholly fast vpon rockes and stones in manner of moss.
1753. Chambers, Cycl. Supp., Lichen, liverwort in botany, the name of a genus of mosses.
1759. Stillingfl., Gedner’s Use Curiosity, Misc. Tracts (1762), 180. The vertues of the lichenes or liverworts upon animate bodies … are not inconsiderable.
2. One of a class of cellular cryptogamic plants, often of a green, grey or yellow tint, which grow on the surface of rocks, trees, etc. Also collect.
According to the modern theory, now generally accepted, the lichen is a fungus parasitic upon an algal, whose form is somewhat modified by the influence of the parasite.
[1601. Holland, Pliny, II. 169. As well in this wild kind as in planted Plum trees of the hortyard, there is to be found a certain skinny gum, in Greek called Lichen, which hath a wonderfull operation to cure the rhagadies or chaps.]
1715. J. Delacoste, trans. Boerhaave’s Aphorisms, 313. The famous earthy ash-colour’d Moss call’d Lichen.
1789. E. Darwin, Bot. Gard., II. (1791), 29. Where frowning Snowden bends his dizzy brow … Retiring lichen climbs the topmost stone.
1796. Coleridge, To Yng. Friend on Domestic. with Author, 4. Where … coloured lichens with slow oosing weep.
1830. Lindley, Nat. Syst. Bot., 325. Lichens are distinguished by their want of a distinct axis of growth.
1856. Stanley, Sinai & Pal., viii. (1858), 320. Aged trees covered with lichen, as if the relics of a primeval forest long since cleared away.
1887. Algie, Guide to Forres, 66. The coral-like gray lichen.
1893. Bridges, Shorter Poems, V. Winnowers, 8. The red roofs nestle, oversprent With lichen yellow as gold.
3. Path. A skin disease, characterized by an eruption of reddish solid papules over a more or less limited area.
1657. Physical Dict., Lichen, a tetter, or ringworm.
1727–41. Chambers, Cycl., Lichen, a cutaneous distemper, otherwise called impetigo.
1842. T. H. Burgess, Man. Dis. Skin, 189. Lichen is not confined to any period of life, or to either sex.
1888. Syd. Soc. Lex., s.v., Many authors regard lichen, strophulus, and eczema, as forms of the same disease.
† 4. After a L. use in Pliny: A callous excrescence on the leg of a horse or ass (? = CHESTNUT 6). Obs.
1607. Topsell, Four-f. Beasts (1658), 22. There is a collection of certain hard matter about an asses legs, called ‘lichen,’ which if it be burned and beaten, and put into old oil, will cause hairs to grow out of baldness.
1661. Lovell, Hist. Anim. & Min., 81. The fume of the lichens, helps the falling sickness.
5. attrib. and Comb. a. simple attributive, as (sense 2) lichen-dust, -flora, -fungus, -moss, -spot, -thallus, -tuft; (sense 3) lichen-eczema, -spot; b. instrumental, as lichen-clad, -clothed, -crusted, -laden, -matted, -tasselled adjs.; c. similative, as lichen-green, -like adjs.; lichen-starch, a kind of starch associated with lichenin in Iceland-moss.
1848. Chambers’ Inform., I. 563/2. A stunted *lichen-clad bole.
1859. Jephson, Brittany, vii. 95. An immense *lichen-clothed menhir.
1886. H. F. Lester, Under two Fig Trees, 232. An old boundary stone *lichen-crusted.
1880. G. Meredith, Trag. Com. (1881), 117. He snapped the *lichen-dust from his fingers.
1900. J. Hutchinson, Archives Surg., XI. 195. The patient had suffered from *lichen-eczema from the age of 20.
1857. W. A. Leighton (title), The *Lichen-Flora of Great Britain.
1875. Bennett & Dyer, trans. Sachs’ Bot., 273. Algæ known as the hosts of *Lichen-fungi.
1898. Daily News, 8 Oct., 6/4. Folds of *lichen-green velvet about the shoulders.
1889. Hissey, Tour in Phaeton, 49. The old buildings … with … *lichen-laden roofs.
1885. H. O. Forbes, Nat. Wand. E. Archip., 101. Blocks of weather-beaten, *lichen-matted trachyte.
1860. Ruskin, Mod. Paint., V. VI. x. § 25. The silver *lichen-spots rest, star-like, on the stone.
1897. J. Hutchinson, Archives Surg., VIII. 223. The initial stage was a lichen spot, of which there were many around the patches.
1897. Mary Kingsley, W. Africa, 572. The heavily *lichen-tasselled fringe of the forest-belt.
1856. W. L. Lindsay, Pop. Hist. Brit. Lichens, 39. The … tissues of the *Lichen-thallus.
1832. R. Cattermole, Becket, etc. 191. Ashes … gray with *lichen-tufts.
Hence Lichenless a., destitute of lichens.
1843. Ruskin, Mod. Paint., I. II. I. vii. § 36. His very rocks are lichenless.
