Sphagnum squarrosum is also commonly known as the spread-leaved peat moss due to the appearance of the branch leaves on the gametophyte. The leaves narrow abruptly towards the ends and turn backward from the stem giving them a tongue-shaped look. The name squarrosum is also in reference to its appearance, meaning "scabby" in Latin, describing the scale-like look of the stem leaves.

The gametophyte is robust with a prominent terminal bud and varies in color from bright- or pale-green to yellowish to a bluish-green. The branches are in fascicles of five with two of them being spreading. The branch leaves are wide spreading squarrose (spreading at right angles), narrowing abruptly and curving inward towards the end of the leaf. The hyaline cells of the branch leaves are convex on both surfaces and are often papillose or "rough" on the side with overlying green cells. The stem leaves are large, long, and oblong shaped. The hyaline cells of the stem leaves are mostly undivided and the walls are almost completely resorbed on the outer surface.

The sporophyte has a large, spherical spore case that is dark brown to black in color and is very numerous. In all other ways the sporophyte is the same as all other Sphagnum. The sporophyte consists of the spore case and "foot", instead of a seta, that elevates the capsules when they become mature. The opercula has a flattened look like an inverted saucer and there are no peristome teeth. Sphagnum has a very unique spore dehiscence where gaseous material builds up within the sporangium and when the pressure gets great enough the operculum is popped off and the spores are violently dispersed.

Sphagnum grows in wet habitats such as mires, bogs, and lakes and is especially fond of glacier formed lakes. The greatest bulk of Sphagnum distribution is in the North Temperate and Boreal zones, including Europe and the United States. It also grows at high altitudes in South America, and Australia. Small amounts of Sphagnum can be found in some unusual habitats like around hot springs in many parts of Iceland.

Sphagnum grows upwards, decays slowly from beneath, accumulating as waterlogged peat, which then can be used in various ways by humans. Sphagnum also has an amazing water holding capacity absorbing up to twenty times its dry weight. Because of these characteristics peat has been used in many ways over the years. It has been used as fuel, bedding, surgical dressing and baby diapers- because of its absorbency, insulation and has a great importance in potting, mulching, and packing still today.

References

1. Bland, John H. Forests of Lilliput. Prentice-Hall, Inc., New Jersey. 1971.

2. Crum, Howard. Mosses of the Great Lakes Forest. University of Michigan. 1983.

3. Schofield, W.B. Introduction to Bryology. Macmillan Publishing Company. New York. 1985.

Written by Mara Ginther