Today’s Wonder of the Day was inspired by Nena. Nena Wonders, “Does moss really only grow on the north side of the tree?” Thanks for WONDERing with us, Nena!

Long, long ago (about 540 million years ago, to be exact), a special group of plants with a sense of adventure began making the journey from water to land. The plant? Moss!

There are thousands of known species of mosses. A hardy plant, it has been found in habitats ranging from the humid tropics to the polar regions, fallen logs to lakes, rivers, and streams. In fact, moss has been found just about everywhere, except in salt water.

Moss is a relatively uncomplicated plant, lacking the leaves, stems, roots, and buds we often associate with “vascular plants" such as ferns, pine trees, and flowers. As a non-vascular plant, the body of moss has no roots; rather, it uses tiny threads to anchor itself to the stones, trees, or ground where it grows.

If you asked moss to describe its dream home, it would likely reply: cool, moist, and dark. Most species prefer shady ground, rock ledges, or tree trunks. Though moss prefers moist environments, it has adapted to survive periods of dry weather.

If you come across a patch of moss that has turned brown or black, it may appear dead, but add a little water and you might be surprised. Many times the plant will turn green and begin thriving again once moisture is reintroduced!

Conventional wisdom has long proclaimed that moss clumps grow on the north side of a tree, but this is only partially true. In the northern hemisphere, the Sun shines from the south, which means the north side of a tree trunk is typically the shadiest.

This, of course, makes moss happy, but don't pack your compass away just yet, or you may find yourself WONDERing which way to turn. If conditions are favorable, moss will grow just about anywhere. In a shady forest, it can thrive on all sides of the tree — north, south, east, or west.

Though they may not make reliable compasses, mosses are very helpful plants. The first to establish themselves on rocky land, they break down rock and soil, creating a more hospitable environment for vascular plants to move into the neighborhood. Their ability to absorb moisture also allows them to act as sponges, soaking up rainfall and helping prevent erosion of the landscapes where they live.

People have used mosses for a variety of purposes. During World War II, Sphagnum, a certain variety of moss, was used to dress soldiers' wounds. In addition to absorbency, it was also found to have mild antibiotic properties. In Mexico, moss is used as a Christmas decoration, and many Japanese gardeners cultivate mosses to add a sense of age and calmness to their gardens.

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