Missouri Mosses

By Cynthia Andre | August 2, 2001
From Missouri Conservationist: Aug 2001

Moss drapes itself around trees and boulders like warm, cozy shawls. It carpets the banks of intermittent streams and glistens like diamonds beside seeps and springs trickling up from the rocks. These areas are beautiful in their own right, but mosses enrich our Missouri landscape.

Mosses generally prefer cool, moist, unpolluted areas. They grow on trees, both living and dead. They grow on soil, in streams and even on the barren, dry rocks of glades and shut-ins. Some also thrive in man-made habitats, including rooftops, especially thatched, slate and shake roofs. They also inhabit cement surfaces and disturbed banks along trails and roadways.

Each species of moss, however, grows only in specific habitats. These habitats are typically distinguishable by temperature, available moisture and light and the texture and chemistry of the substrate. For example, some species of mosses growing on rocks may be restricted to calcareous rock, such as limestone and dolomite. Others may be restricted to siliceous rock, such as sandstone and granite.

Because many mosses are able to grow on rock or on open ground, they are important in preventing soil erosion and in building soil, thus allowing larger plants to move into previously uninhabitable areas. Also, many small insects live in the moist, protected habitat created by these small plants. Some, such as the water bear, or moss piglet, actually feed on the moss itself. In northern tundra regions, moss is important food for some large animals. In addition, a number of species of birds use mosses in their nests.

People also have benefited from mosses. Not many years ago, people would use highly absorbent peat moss (in the genus Sphagnum) for diapers and as lining for cribs. When cotton was in short supply during WWI, peat moss was used for bandages. Although more difficult to use, it was more absorbent than cotton and had natural antibiotic qualities that fought infections.

Today, dried mosses are used as packing materials for fruits and vegetables, fragile items and live plants. When used as a soil amendment, they can improve the ability of sandy soils to hold moisture. When added to clay, they lighten the soil, improving aeration and drainage.

Probably the most significant economic use of mosses today, however, is the widespread use of peat moss for fuel in other countries, which is estimated to be a billion dollar industry.

Living moss is also used for monitoring heavy metal contamination in streams and rivers. Like lichens, it is also used to monitor air pollution.

Although dried mosses are used for medicinal purposes by herbalists, fresh moss generally has an unpleasant taste. It's often described as similar to raw green beans. Other species are reported to have a peppery taste, and one species of moss has been described as overly sweet.

Most mosses are so small that people generally can't tell them apart from liverworts, algae, lichens and very small flowering plants. What has become known as reindeer moss, for example, is actually a lichen. Spanish "moss" isn't a moss either. It is a relative of the pineapple and bears tiny flowers each year.

Mosses are small plants, but they do not produce flowers or seeds. Instead, they reproduce asexually by fragmentation of plant parts and by spores produced in a capsule at the end of a short stalk called a seta. Their stems, leaves and rootlike structures distinguish them on land from lichens, and in water from the branching filaments of algae, which lack leaflike structures.

Mosses contain chlorophyll, which enables them to produce their own food, but they do not have true roots or any way to transport water and minerals from the soil to the leaves, where photosynthesis occurs. The leaves are often only one cell thick and absorb water and minerals directly into the chlorophyll-containing cells. This arrangement seems to leave mosses vulnerable to desiccation when there is no moisture available, but most species have developed the ability to tolerate periods of dehydration.

Many mosses found in Missouri and particularly in the Ozarks are also found in southern Appalachia, southern Mexico and eastern Asia. These species are separated today because of geological events, such as rising sea levels and glaciations, that eliminated suitable habitat between these areas.

During the period when glaciers were expanding and retreating, some arctic-boreal species migrated to southern Missouri. A few of these northern plants were able to remain behind in moist, cool habitats such as the north-facing slopes and bluffs along the Jacks Fork River in Shannon County. During dry and warm interglacial periods, western species colonized Missouri and still remain today.

The color of Missouri's approximately 306 species of mosses varies from black and brownish greens to yellow, golden and whitish green.

Our mosses range in height from extremely tiny to almost four inches tall.

Missouri's mosses are divided into three major categories, based on their growth patterns. Pleurocarps grow parallel to the ground, and their branching is erect. Acrocarps grow upward from the ground as a single stem and have little or no branching. Dendroids are composed of the few mosses that resemble a small tree. Although you may need a microscope to differentiate between many of the mosses, some of Missouri's more common species can be easily recognized. Fern mosses (in the genus Thuidium), for example, often form thick, luxurious mats of moderately large branches resembling the fronds of a fern. They live in open, sunny places, as well as in moist, shaded areas.

Windswept moss (Dicranum scoparium) is frequently seen on ridges, wooded slopes and rock ledges. It forms thick mats of pale green tufts that look somewhat like tall, waving grass when viewed from a low-flying plane. This attractive moss is commonly used in moss gardens in Japan. Pin-cushion moss (in the genus Leucobryum) forms white-green, dense, spongy, cushionlike tufts, sometimes reaching a foot in diameter. It is usually found on the rocky soil of ridges, but may also grow on rock ledges and near tree bases.

One of the few peat mosses of Missouri, Sphagnum subsecundum grows on soil at the edges of creeks and streams, particularly in the southeastern quarter of the state. The plants are erect and whitish or bright green, often tinged with purple, pink, red or brown. The branches occur in groups called fascicles and are frequently most densely crowded toward the top of the stem.

Sphagnum mosses flourish in wetland areas and are able to lower the pH in these habitats. Decomposing organisms cannot thrive in the acidic environment, so partly decayed organic material builds up over time, forming peat. The process of peat formation usually takes place in regions cooler than Missouri, however.

One of the two dendroid mosses of Missouri, pine moss (Climacium americanum) can be found throughout the state on moist, shaded soil, usually on ledges and at the bases of bluffs. The pine moss's tree-like growth habit is unlike any other species in this habitat.

It's fun to study the mosses. If you collect them, take only small samples that you can place in small bags or envelopes to dry. Do not collect on public or private lands without permission, and refrain from disturbing small populations or endangered species.

Several publications can help the amateur collector with moss identification. Thomas and Jackson's "Walk Softly Upon the Earth," Conrad's "How to Know the Mosses and Liverworts," and Redfearn's "Mosses of the Interior Highlands of North America" are all good reference books. The Ozarks Regional Herbarium at the Southwest Missouri State University in Springfield or the Crosby Bryophyte Herbarium of the Missouri Botanical Garden in St. Louis may be able to help you identify particularly difficult species.

This Issue's Staff

Editor - Tom Cwynar
Managing Editor - Bryan Hendricks
Art Editor - Dickson Stauffer
Designer - Tracy Ritter
Artist - Dave Besenger
Artist - Mark Raithel
Photographer - Jim Rathert
Photographer - Cliff White
Staff Writer - Jim Low
Staff Writer - Joan McKee
Composition - Libby Bode Block
Circulation - Bertha Bainer