Bryophytes Were Not Always Grass
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The Green Beneath O he green beneath our feet is Mosses are part of a section of the Bryophytes were not always grass. plant world called bryophytes. Num - As we hike through the bering about 16,000 species, the first plants to woods, stroll through a park bryophytes comprise three groups or or, to the dismay of some phyla of the Kingdom Plantae and are occupy terrestrial homeowners, walk through second only to flowering plants (about our yard, we may be step- 250,000 species) in the number of habitats. ping on green clumps, mats plant species known to exist. Mosses or even springy carpets of (Phylum Bryophyta) are the most Tmoss. Because of their small stature, abundant of the three bryophyte cate - Story By Ray Stotler and these plants, even though ubiquitous, gories worldwide, with nearly 10,000 Barbara Crandall-Stotler tend to be an inconspicuous part of the species. Liverworts (Phylum Marchan - landscape and typically go unnoticed tiophyta) account for approximately Photos By Li Zhang and by most. Every patch is made up of 6,000 species, and hornwort (Phylum Barbara Crandall-Stotler hundreds or thousands of individual Anthocerotophyta) species number plants, each with a stem and spirally about 200. Liverworts are the most 16 / Outdoor Illinois December 2007 arranged leaves. ancient group of land plants, with Pear-shaped urn moss Physcomitrium pyriforme The spore-bearing capsules of the worts are bilaterally symmetric (mirror pear-shaped urn moss look like images halves), with distinctly different dorsal and ventral surfaces. In mosses, upside-down pears. When ripe, they the insertion of the leaves on the stem become urn-shaped cups. is transverse and the leaves are undivid - ed, long and often tapered to a pointed known as microhabitats, exist. Most tip. The leaves of liverworts lie flat bryophyte species are found in only one against the substrate and can be divided microhabitat, although some species are into two or more parts, or if undivided adapted to a broad range of habitats. are generally a rounded shape. In moss - The three groups of bryophytes can es, all of the leaves of a shoot are simi - be distinguished if examined with care. lar. But in liverworts, the two rows of This can easily be done by using a mag - leaves that can be seen from the upper nifying lens and, once a person has side are larger and different from the observed the structural differences, it smaller, hidden leaves on the underside becomes fairly straightforward. All surface. Overall, liverworts are much mosses and most liverworts are made smaller than mosses. up of cylindrical stems with either spi - ur Feet rally arranged leaves (mosses) or leaves Carolina hornwort their fossils dating back to more than Phaeoceros carolinianus 475 million years ago. arranged in two or three rows (liver - Illinois’ rich flora includes an out - worts). Some mosses grow erect, form - standing array of bryophytes, with ing turfs or tight cushions, while other approximately 350 species of mosses, species form compacted mats or loose 140 species of liverworts and four wefts. Liverworts and hornworts typi - species of hornworts. These plants cally grow prostrate and appressed to occupy an assortment of habitats, their substrates. With rare exception, including disturbed ones, like plowed the leaves of mosses are evenly spaced fields and roadside banks, as well as all around the stem, while leafy liver - native woodlands and grasslands. They commonly grow on trees, logs, rocks Look for Carolina hornwort in the and soil, and some may even be sub - spring, growing on the compact soil merged in or floating on water. The greatest diversity of our state’s bryoflora along trails in Illinois woodlands. In occurs in woodlands and canyons, the fall it can be found on river banks where small, specialized environments, exposed by receding water. December 2007 Outdoor Illinois / 17 Great scented liverwort Conocephalum conicum Common feather liverwort Plagiochila porelloides Liverworts are the most ancient The spore-producing phase remains family of green plants. Scientists have attached to the plant by embedded tis - sue; it is through this tissue that nutri - examined chemical compounds ents move from the green plant to nur - produced by liverworts and found that ture the spore-developing process. they can inhibit the growth of certain Spore-producing structures are fre - Rivulet liverwort quently seen emerging from mosses Pellia epiphylla bacteria and tumor cells. and hornworts. In mosses this consists that produce sex cells or gametes, i.e., of a leafless stalk that bears an enlarged Although all mosses and most liver - sperm or eggs. A male sperm will fertil - spore-producing capsule at its tip. worts are leafy plants, in some liver - ize a female egg and the spore-generat - Hornworts produce elongate, often worts and all hornworts the plant is a ing period of the life-cycle has begun. green, horn-like capsules. The liverwort flattened, ribbon-like thallus. The thal - lus in complex liverworts is differentiat - Hairy Grimmia moss Grimmia laevigata ed into a ventral zone of storage tissue and an upper zone of air chambers that open to the outside by elevated pores. These chambers impart a patterned appearance on the thallus surface. In contrast, in simple thalloid liverworts and all hornworts the air chambers and pores are lacking so that the thallus has a very smooth texture. Bryophytes reproduce by means of microscopic, one-celled spores. These spores germinate and grow into popula - tions of sexually mature plants. Each bryophyte population consists of count - less gametophytes, individual plants A pioneer species, hairy Grimmia moss grows on rocks. The species can be identified by the long, white, hair-like tips on each leaf. 18 / Outdoor Illinois December 2007 This species of Sphagnum moss grows in “hanging bogs,” found draped over the tops of southern Illinois canyons. Because so few biologists study these plants, few data have been collected regarding the need for bryophyte con - servation in Illinois. As of 2007, no bryophytes have been listed as either endangered or threatened in our state. To conserve the diversity of bryophytes, as well as associated organisms, it is essential to preserve the diversity of nat - ural habitats that they occupy. Compact peat moss Sphagnum compactum Drs. Ray Stotler and Barbara spore phase is rarely seen, but can be They flourish particularly well in moist, Crandall-Stotler are Emeriti Professors recognized by their fragile, white stalks humid forests like the fog forests of the of Plant Biology at Southern Illinois tipped with shiny black capsules. Pacific northwest or the rain forests of University-Carbondale. Dr. Li Zhang When the capsules are mature they the southern hemisphere. Their ecolog - was a Post-Doctoral Fellow at SIU-C and has returned to his native China dry and open, dispersing the spores in ical roles are many. They provide as a research scientist at the Fairylake breezy weather, and the cycle then seedbeds for the larger plants of the Botanical Garden in Guangdong. repeats. In most of our bryophytes, community, they capture and recycle spore release occurs in February to nutrients that are washed with rainwa - April in southern Illinois on into May or ter from the canopy and they bind the Juniper moss June in the northern parts of the state. soil to keep it from eroding. Polytrichum juniperinum Bryophytes grow in practically every In Illinois the greatest diversity of kind of habitat with the exception of mosses is found in woodlands, especial - hot springs and salty ocean waters. ly mid-slope to upland sites where they occur on exposed soil, rocks, logs and tree trunks. Most liverworts, in con - Teaching About trast, require a more mesic habitat and Bryophytes? so are found on shaded soil, rocks, logs and tree bases in bottomland woods, he DNR Division of Education pro - ravines, and in canyons where water T duced an Illinois Bryophytes poster seeps through the rocks. The horn - to assist teachers with their lessons worts that occur in Illinois are most about these unique organisms. Along with images of 25 bryophyte species commonly found growing on disturbed, indigenous to the state, life history compacted soil. This habitat may be information and other items of interest found in farm fields before they are are included. Order the poster at plowed in the spring or along the edge Spoon-leaved moss Bryoandersonia illecebra www.idnrteachkids.com. of dirt paths in forests. In the fall, look On March 28, 2008, Ray Stotler and for hornworts and liverworts in draw- Barbara Crandall-Stotler will lead an Illi - nois Bryophytes workshop for teachers down areas where the water has reced - at Giant City State Park in Makanda as ed along river banks, lake shores and part of the DNR ENTICE (Environment streams banks. and Nature Training Institute for Con - servation Education) program. Registra - tion is required. For the workshop Mosses and liverworts grow on all description and to register, visit www. ilcf.org/Workshop/Courses.asp. Con - continents—including Antarctica. Most tinuing Professional Development Illinois species grow throughout the Units are available. year, even during harsh winter months. December 2007 Outdoor Illinois / 19.