Lichenes
Read about Lichenes in the Standard Cyclopedia of Horticulture
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LICHENES (Lichens) Green, gray or highly colored plants of very diverse habit and habitat, either thalloid, fruticose or crustaceous, and growing on the soil, bark of trees, rocks, or rarely on foliage: propagation by division of the thallus or by the separation of special minute powdery parts (soredia): spore-reproduction by ascospores borne in perithecia or apothecia, rarely by basidiospores. The lichen thallus is not a single organism, but is probably a symbiotic structure, comprised fundamentally of fungus hyphae between which many unicellular green algae are distributed, usually in a définite fashion. The fungi belong to the Ascomycetes in the great majority of cases, rarely to the Basidiomycetes. The algae may belong to the Chlorophyceac, in which case they are unicellular, or to the Cyanophyceae, in which case they are either unicellular or in chains. Because the symbiotic structure behaves as a unit, it has been decided to continue to treat the lichens as a class by themselves, rather than to consider the algal and fungal components independently in their respective groups. Except as soil-producers, lichens are of little economic importance: Cetraria islandica furnishes Iceland moss; Sticta pulmonaria was once used in medicine; Cladonia rangiferina furnishes the main food of the reindeer in Lapland, and, possibly, of other arctic animals; Roccella tinctoria of Africa and the East Indies is the source of the chemical indicator, litmus and of the dye orchil or orseille.
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References
- Standard Cyclopedia of Horticulture, L. H. Bailey, MacMillan Co., 1963
External links
- w:Lichenes. Some of the material on this page may be from Wikipedia, under the Creative Commons license.
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