Forest Preserve District of Cook County, Illinois
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Nature Bulletin No. 332-A   February 15, 1969
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation

Few sights are more restful and attractive than a moss-covered rock or log in a deep woods or along a secret shady stream. At close range, in a child's imagination, a carpet of moss is a fairy forest where the "little people" make magic beneath its make-believe "trees".

The word "Moss", strictly speaking, belongs to a certain definite group of tiny green plants, but in common usage many other small greenish plants are also called mosses. For example, reindeer moss is really a lichen. Spanish moss is a flowering plant related to the pineapple. It grows on trees in festoons that dangle like long gray beards. The "moss" on the shady side of a tree trunk is an alga, The true mosses grow from sea level to above the timberline on mountains, and from the moist tropics to the arctic tundras which are blanketed with lichens and mosses. In temperate regions, though not conspicuous, we find them on the soil of old fields, rocks, trunks of trees, and rotting logs; in moist woods and bogs; and even under water in swift streams. Perhaps because of smoke and fumes, they are seldom found in cities.

Mosses furnish no food to man and appear to have little value but they play, and always have played, an essential role in the colonization of land areas by our modern flowering plants. On the barren rocks and areas exposed by glaciation, lichens grew first. When they died, leaving a trace of organic matter, this allowed mosses to follow and, after them, our modern trees and flowers. Mosses are hardy. Even in midwinter the greenest thing you are likely to find is a bed of moss.

Of the 1000 or more species and varieties known to the experts -- and it takes an expert to name some of them -- there are a dozen or more that an amateur with a lens can find and identify in the Chicago region. All are built in the same general way and the Hairy Cap Moss, also called Pigeon Wheat, may be chosen as an example. It is a rather coarse moss, growing on dry open knolls near damp woodlands. In fall or winter it is a greenish-brown cushion of bristling stems. In early summer it is tipped with the vivid green of new growth on top of the old dead growth of previous years. At this time it also sports a forest of shining ruddy stiff bristles each bearing a woolly object like a small grain of wheat. This is covered with a pointed cap which encloses the spore capsule. When the spores are ripe, this cap falls off to expose a beautiful green four-sided "pepper box" which sifts the fine dust-like spores into every passing breeze.

In a damp suitable place, one of these spores sprouts and grows-into a sprawling network -- perhaps the size of your hand -- of green threads which produce knots or buds. Each of these shoots up a leafy stem held erect by fine root-like anchors -- the "trees" of the elfin forest. Some stems are topped with rosettes of leaves set in little cups which produce sperm cells. Melting snow or spattering raindrops carry these swimming sperm cells to egg cells that appear on the tips of other stems. From these, a new spore capsule grows and so the cycle is repeated.

Best known is the Sphagnum or peat moss which grows in bogs and gradually forms peat as it lives and dies. Because each pound of it can absorb as much as 200 times its weight of water and still remain loose, it is harvested on a large scale for use in nurseries, for shipping plants, and for making surgical dressings.

Irish moss, neither green nor a moss, is an edible seaweed used in puddings.

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