DESCRIPTION OF THE LICHENS
| LICHENS ARE CHIMERICAL ENTITIES AND, THEREFORE, HAVE NO NATURAL LINES OF DESCENT |
LICHENS LINKS
| Lichens (LI-kins) is formed from a Greek root that means lick (leicho -λείχω). The reference may be to their use as medicinals. At that time, lichens included some mosses, liverworts, as well as lichens. |
INTRODUCTION TO THE LICHENS
By convention, the lichens are classified as members of the Kingdom Fungi. However, because the fungus (the mycobiont (text with tooltip) The fungal component of a lichen. ) and the alga (the phycobiont (text with tooltip) The algal component of a lichen. ) can live separately in a free-living state, both components should have separate taxonomic designations. The difficulty is compounded by the lichen itself. The symbiotic chimeroid structure called the lichen truly is a different organism from either of its fungal or algal components thus it should have its own “taxonomic” designation, one based on form rather than phylogeny. I have adopted the convention of the fungal classification, but we include a description of the Form (text with tooltip) Binomial name given based on morphology rather than phylogeny. -Phylum Lichens in recognition of the uniqueness of the particular symbiosis. Certainly, lichens as a taxon follow the dictum of deux veritas.
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| A. Peltigera, a
foliose
(text with tooltip)
Leaf-like.
lichen. Image taken from http://www.ac.wwu.edu/~fredr/Images/Peltigera%20membranacea.jpg | B. Cladonia, a
fruticose
(text with tooltip)
Shrub-like.
lichen. Image taken from http://web.uvic.ca/ail/Cladonia%20macilenta.jpg | C. Parmelia, a foliose lichen. Image taken from http://www.ac.wwu.edu/~fredr/Images/Parmelia%20sulcata.jpg | D. Usnea, a fruticose lichen. Image taken from http://www.ac.wwu.edu/~fredr/Images/Usnea%20rigida.jpg |
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| E. Pyrenula, a
crustose
(text with tooltip)
Crust-like thallus; stretched over and firmly fixed to substrate.
lichen. Image taken from http://www.biology.duke.edu/dnhs/pics/Pyrenula.jpg | F. Calicium, the spike lichen. Image taken from http://www.cas.cz/ziva/cisla/0502/04.jpg | G. Opegrapha, a crustose lichen. Image taken from http://www.uni-bayreuth.de/departments/planta2/ass/robert/lichens/ | H. Lepraria, a crustose lichen. Some others in this group are
squamulose
(text with tooltip)
Scaly
. Image taken from http://www.toyen.uio.no/botanisk/lav/Photo_Gallery/Lepraria/ |
| LITERATURE CITED Ahmadjian, V. 1967. The Lichen Symbiosis. Blaisdell Publishing Co. Waltham, Mass. 152 p. Hale, M. E. 1979. How to Know the Lichens. 2nd ed. Wm.C. Brown Publishers. Dubuque, IA. Margulis, L. and K. Schwartz. 1998. Five kingdoms, an illustrated guide to the phyla of life on earth. 3rd Edition. W. H. Freeman and Company. New York. Nash, T. H., III, ed. 1996. Lichen Biology. Cambridge University Press. New York. 303 pp. |
| By Jack R. Holt. Last revised: 03/10/2013 |
