LICHENS – A TAPESTRY OF LIFE
by Donna Bollenbach
The tiny moss has
been the theme of many a gifted poet; and even the despised mushroom has called
forth classic works in its praise. But the Lichens, which stain every rock, and
clothe every tree, which form:
Nature’s
livery o’er the globe
Where’er
her wonders range
Have been
almost universally neglected, nay despised.
Lauder
Lindsay
Imagine our
continent after the last ice age: Glaciers cut deep gorges in the land and miles
of granite boulders, silt and the bones cover the hills and plains of North
America. Life has all but disappeared, but there is hope for new life in a simple
living entity that is neither plant nor animal, the lichens.
Lichens on a rock in Yellowstone National Park. |
For this
reason, lichens and mosses are considered pioneers of succession. Today, they
are still the primary plant-like species of the deserts and tundra where they thrive
in conditions that are inhospitable to most other plants. They are also an
important source of food for animals in those extreme climates where other
vegetation is scarce.
TAPESTRY
– from the Greek word tapis for carpet; a fabric
with a woven design resembling tapestry, varied entwined and intricate (i.e.
the tapestry of life).
Lichen, a
living organism that is neither plant nor animal, is one of nature’s true
tapestries. A fungus and a suitable green
alga or cyanobacteria (blue-green alga), intricately woven together in a
symbiotic union, lichens carpet trees, rocks, soil and other substrates with their
rich colors and textures.
There are over
14,000 species of lichen living in nearly every habitat in the world. In addition to
rocks, lichen grows on an array of natural and manmade substrates, including
bark, stone, wood, soil, leaves, moss, bone, human artifacts and even some
living creatures. Unlike the pioneer lichens that break down rocks, lichens
found on living substrates are not parasitic, they simply use the host as a
place to live.
FORM & BEAUTY
Yet
lovely was its pleasant shade;
Lovely
the trunk will moss inlaid;
Lovely
the long-haired lichens grey;
Lovely
its pride and its decay.
Mary
Russell Mitford
The task of
defining and classifying lichens is a daunting one for scientist. The
international Association for Lichenology defines lichen as “an association of
a fungus and photosynthetic symbiont resulting in a stable vegetative body
having a specific structure.” Noted Lichenologist, Trevor Goward, went further
to describe lichen as “fungi that have
discovered agriculture.”
Scientifically,
lichens are classified by one of four general growth forms: Foliose (leafy,
lobed and most often with an upper and lower cortex), Fruiticose (hairy, tubular,
multi-branching strands or lacey balls with a single cortex), Crustose (crusty,
flat patches that can be somewhat smooth or thick and bumpy) and Squamulose (an
intermediate between the Crustose and Foliose, with thick, scaly shingles).
A combination of lichen forms and mosses on tree bark. |
While these
scientific terms do suggest the general shape of the lichen classes, they do
little justice to the lichen’s true beauty.
The Foliose lichens have a leaf-like form. They have many lobes., often curling slightly inward and layered on top of each other.
The Foliose lichens have a leaf-like form. They have many lobes., often curling slightly inward and layered on top of each other.
Foliose lichens on a tree. |
The Fruticose lichens are highly branched. They can be thin and stringy, or round, lacy and soft in appearance. Some of the Fruticose lichens found in the scrub look like puffy greenish gray clouds.
Fruiticose lichens, or powder puff lichens in the Florida Scrub. |
The Crustose lichens are flat, often circular patches, tightly adhered to their substrate. Colorful fruiting bodies adorn their cortex.
While many
lichens are white to greenish-grey to brown, many are bright red, yellow or
orange. Even a green or gray lichen may be adorned with a bright red fruiting
body. Some of the fruiting bodies are mere dots, while others are more like
little mushrooms. The combination of color and texture in lichens are as varied
as the substrates they live on, and have given many a painter or photographer a
reason to pause and admire nature's finest fabric.
And these are all the reasons I Love Lichens!
If you also love Lichens, check out this great book: "Lichens of North America" by Brodo, Sharnoff & Sharnoff. It is rather expensive, but it is nearly 800 pages of fascinating information and beautiful color images.
Foliose lichen (British soldiers) with an Earth Star (fungus) in the center. |
Donna Bollenbach
If you also love Lichens, check out this great book: "Lichens of North America" by Brodo, Sharnoff & Sharnoff. It is rather expensive, but it is nearly 800 pages of fascinating information and beautiful color images.
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