Pictorial Supplement to The Fifth Kingdom  -  Chapter 7

Lichens -  Dual Organisms   
(24 pictures)
(CD-ROM has full text, 66 pictures and one video sequence)

lich1.jpg (7137 bytes) Exposed rock faces on the north shore of Lake Superior, Northern Ontario, almost entirely covered by lichens.
lich2.jpg (7549 bytes) Landscape near Schefferville, northern Quebec.  The spruce trees are there courtesy of their ectomycorrhizal fungal partners, and the ground cover is entirely composed of lichens.
lich3.jpg (8170 bytes) crustose lichens on tree bark - road to Dingo Beach, Queensland, Australia.
lich4.jpg (6649 bytes) Verrucaria zone on rocks along shore at   Letite, New Brunswick, Canada (also seen along west coast)
lich22.jpg (8160 bytes)

a basidiolichen with Omphalina (Tricholomataceae) as the mycobiont, the green alga Coccomyxa as phycobiont.   The association is sometimes called Botrydina (courtesy of Fred Notzel).
  
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lich12.jpg (6958 bytes) model of a lichen thallus, showing round algal cells among fungal hyphae.
lich13.jpg (8192 bytes) vertical section through lichen thallus: algal cells are stained dark blue.
lich7.jpg (8635 bytes) foliose and crustose lichens on rock, Highwood Pass, Alberta, Canada
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lich8.jpg (8148 bytes) Cladonia rangiferina ("reindeer moss") (Cladoniaceae, Lecanorales), with sterile, branched podetia
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lich21.jpg (6261 bytes) a Cladonia sp. showing basal squamules, erect podetia and apical brown apothecial ascomata
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lich9.jpg (6067 bytes) Pilophorus aciculare (Stereocaulaceae,   Lecanorales) - podetia on a stone
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lich20.jpg (9755 bytes)
colonies of Umbilicaria (Umbilicariaceae, Lecanorales): the large black dots are apothecial ascomata
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lich17.jpg (8769 bytes) Icmadophila ericetorum (Leotiales) on rotten stump, with convex, pink apothecial ascomata.
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lich11.jpg (11098 bytes) discolichens on tree bark   The orange (left) and brown disks (right) are apothecial ascomata
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lich27.jpg (5333 bytes) the discolichen Letharia vulpina on a small conifer branch
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lich14.jpg (7438 bytes) vertical section through half of an apothecial ascoma of Physcia (Physciaceae, Lecanorales).   Algal cells (pale green with dark centre) are present in the margin and underside of the ascoma. 
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lich18.jpg (5433 bytes) a pyrenolichen, Pyrenula nitida (Pyrenulaceae, Pyrenulales) in tree bark.
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If you'd like to see more (and better) pictures of lichens, please visit the following web site:
http://www.lichen.com/portraits.html     Just click on that address to go there...
These are pictures from a new book on the Lichens of North America, that will be published
in the year 2,000.  There is more about lichen biology at:
http://www.lichen.com/biology.html       
  
But there are things about lichens (other than their appearance) that you need to know,
so please keep on scrolling to the pictures below -

lich16.jpg (5653 bytes) tips of archaeasceous asci
lich19.jpg (4552 bytes) soredia - cells of a green alga caged by fungal hyphae.
lich15.jpg (7236 bytes) steps in lichen synthesis (SEM)
lich23.jpg (7622 bytes) a lichen-encrusted tombstone, the kind of thing that inspired lichen-dating
lich25.gif (47401 bytes) distribution of fruiting (solid red dots) and sterile (red outlines) lichens in Montreal.  Small red dots indicate absence of the lichens.
lich26.gif (17087 bytes) sulphur dioxide levels in Montreal.  Higher values correlate strongly with the occurrence of sterile lichen thalli, or absence of lichens (see above). 
Lichens are thus seen to be sensitive indicators of air pollution.
lich24.jpg (6509 bytes) Ascoma of Mycosphaerella ascophylli embedded in the thallus of the brown seaweed, Ascophyllum nodosum. The fungus is always present, and may indicate a kind of reversed lichenization - or a universally distributed parasite.
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Mycologue Publications 2001