While snowshoeing through the school forest in the fog and mist with temperatures in the mid to upper 30s, I noticed this tree stump. I thought the vegetation on top mixed with snow and pine needles made an interesting photo. As I was uploading the pictures this morning I decided to try to identify the vegetation. Is it moss? Lichen? What is the difference?
Mosses are small, soft plants that are typically 0.4–4 inches tall. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems. There are approximately 12,000 species of moss classified in the Bryophyta. Botanically, mosses are non-vascular plants. In addition to lacking a vascular system, the plant's cells are haploid for most of its life cycle. Most kinds of plants have two sets of chromosomes in their vegetative cells and are said to be diploid, i.e. each chromosome has a partner that contains the same, or similar, genetic information. By contrast, mosses and other bryophytes have only a single set of chromosomes and so are haploid (i.e. each chromosome exists in a unique copy within the cell). The life of a moss starts from a haploid spore. The spore germinates to produce a mass of thread-like filaments (protonema), or a flat mass (thalloid). Moss typically looks like green felt, and may grow on damp soil, tree bark, rocks, concrete, or almost any stable surface. From the moss mat, which is a transitory stage in the life cycle, grows the gametophore ("gamete-bearer") that structurally differentiates into stems and leaves. A single moss mat may develop several gametophore shoots, resulting in a clump of moss. A picture of moss taken from the Internet is below.
Lichens are composite organisms consisting of a symbiotic association of a fungus with a photosynthetic partner, usually either a green alga or cyanobacterium. The combination organism lichen is very different from the separate components of fungus and alga. Lichens occur in some of the most extreme environments on Earth including arctic tundra, hot deserts, rocky coasts, and toxic slag heaps. However, they are also abundant as epiphytes on leaves and branches in rain forests and temperate woodland, on bare rock, including walls and gravestones, and on exposed soil surfaces. Many lichens are vulnerable to environmental disturbance, and may be useful to scientists in assessing the effects of air pollution, ozone depletion, and metal contamination.
The body of lichens may resemble simple plants in form and growth. The fungus surrounds the algal cells providing structure. The algal or cyanobacterial cells are photosynthetic, and as in plants they reduce atmospheric carbon dioxide into organic carbon sugars to feed both symbionts. Both partners gain water and mineral nutrients mainly from the atmosphere through rain and snow. The fungal partner protects the alga by retaining water, serving as a larger capture area for mineral nutrients and, in some cases, provides minerals obtained from the substrate. Living as a symbiont appears to be a very successful way for a fungus to derive essential nutrients, as about 20% of all fungal species have acquired this symbiotic mode of life.
From what I can tell by comparing the vegetation on the stump picture above with those on the internet, the vegetation is reindeer moss -- which is actually a lichen. The lichen is used as a traditional remedy for removal of kidney stones by the Monpa in the Himalayas. Other native peoples have used reindeer lichen for food by crushing the dry plant and then boiling it or soaking it in hot water until it becomes soft. They eat it plain or, preferably, mixed with berries, fish eggs, or lard. They also boil Reindeer lichen and drink the juice as a medicine for diarrhea.
As I continued snowshoeing through the school forest, I noticed all the droplets that accumulated on various surfaces. Below is a picture documenting the accumulation of moisture dripping from pine needles.
A typical school forest scene....
It was a long snowshoe to the Lake Superior bluff and back (six miles total) with the soft slushy snow. Here is an updated photo of what the icebergs look like east of town.
My friend, Renee, came over for dinner. Her husband, Bob, is a great brook trout fishermen. Renee thawed out and brought over four huge brook trout. I added the rice medley, broccoli, humus sauce, and mandarin oranges. Thank you Bob -- the trout was delicious!
Tuesday, March 22, 2011
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