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Bryophyta Bryophytes; Mosses; Hornworts; Nonvascular plants

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Higher taxa:  Life   Plantae   Global map IDnature guides: Groups_Plantae, Neotropical_flora Missouri Botanical Garden We parsed the following live from the Web into this page. Such content is managed by its original site and not cached on Discover Life. Please send feedback and corrections directly to the source. See original regarding copyrights and terms of use. Image, SIUC / College of Science Michael Knee, Ohio State University Ari Kornfeld

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© Matt von Konrat, 2004 Frullania pycnantha, Liverwort	© Matt von Konrat, 2004 Thuidiopsis, Moss

Kinds

Amblystegiaceae Andreaeaceae Andreaeobryaceae Anthocerophyta -- Hornworts Anthocerotaceae Archidiaceae Aulacomniaceae Balantiopsaceae Bartramiaceae Brachytheciaceae Bruchiaceae Bryaceae -- Mosses Bryobartramiaceae Bryoxiphiaceae Buxbaumiaceae Calomniaceae Calymperaceae Carrpaceae Catoscopiaceae Chaetocoleaceae Chaetophyllopsaceae Cinclidotaceae Climaciaceae Codoniaceae Cryphaeaceae Cyrtopodaceae Daltoniaceae Dendrocerotaceae Dicnemonaceae Dicranaceae Disceliaceae Ditrichaceae Echinodiaceae Encalyptaceae Entodontaceae Ephemeraceae Ephemeropsidaceae Erpodiaceae Eustichiaceae Fabroniaceae Fissidentaceae Fontinalaceae Fontinaliaceae Funariaceae Gigaspermaceae Grimmiaceae Hedwigiaceae Helicophyllaceae Herzogiariaceae Hookeriaceae Hydropogonaceae Hylocomiaceae Hypnaceae Hypnodendraceae Hypopterygiaceae Isotachidaceae Lembophyllaceae Leptodontaceae Leptostomaceae Lepyrodontaceae Leskeaceae Leucobryaceae Leucodontaceae Lophocoleaceae Lophoziaceae Meesiaceae Meteoriaceae Metzgeriopsaceae Microtheciellaceae Mitteniaceae Mniaceae Myriniaceae Myuriaceae Nanobryaceae Neckeraceae Notothyladaceae Oedipodiaceae Orthorrhynchiaceae Orthotrichaceae Phyllodrepaniaceae Phyllogoniaceae Plagiotheciaceae Pleurophascaceae Pleuroziopsaceae Pleuroziopsidaceae Polytrichaceae -- Hair-cap mosses Pottiaceae Prionodontaceae Pseudoditrichaceae Pterigynandraceae Pterobryaceae Ptychomitriaceae Ptychomniaceae Racopilaceae Regmatodontaceae Rhabdoweisiaceae Rhachitheciaceae Rhizogoniaceae Rhytidiaceae Rutenbergiaceae Schistostegaceae Seligeriaceae Sematophyllaceae Serpotortellaceae Sorapillaceae Sphagnaceae Spiridentaceae Splachnaceae Splachnobryaceae Stereophyllaceae Takakiaceae Tetraphidaceae Thamnobryaceae Theliaceae Thuidiaceae Timmiaceae Trachypodaceae Verdoorniaceae Viridivelleraceae Wardiaceae

Overview

Hornworts, liverworts, and mosses - commonly referred to as bryophytes - are considered to be a pivotal group in our understanding of the origin of land plants because they are believed to be among the earliest diverging lineages of land plants. Mosses, liverworts and hornworts are found throughout the world in a variety of habitats, from the harsh environs of Antarctica to the lush conditions of the tropical rainforests. Bryophytes are unique among land plants in that they possess an alternation of generations, which involves a dominant, free-living, haploid gametophyte alternating with a reduced, generally dependent, diploid sporophyte. Bryophytes are small, herbaceous plants that grow closely packed together in mats or cushions on rocks, soil, or as epiphytes on the trunks and leaves of forest trees. Bryophytes are remarkably diverse for their small size and are well-adapted to moist habitats and flourish particularly well in moist, humid forests like the fog forests of the Pacific northwest or the montane rain forests of the southern hemisphere. Significance of bryophytes Bryophytes have a significant role in contributing to nutrient cycles, providing seed-beds for the larger plants of the community, and form microhabitats for insects and an entire array of microorganisms. Bryophytes are also very effective rainfall interceptors, and the overwhelming abundance of epiphytic liverworts in "cloud" or "mossy" forest zones is considered an important factor in eliminating the deteriorating effect of heavy rains, including adding to hill stability and helping to prevent soil erosion. The chemical compounds of some liverworts are also particularly interesting because they have important biological activities, for example, against certain cancer cell lines, anti-bacterial properties, anti-microbial, anti-fungal, and muscle relaxing activity. Classification Over the last decade, recent advances in DNA sequencing technology and analytical approaches to phylogenetic reconstruction, including the use of ultra-structural, morphological and anatomical data, have enabled unprecedented progress toward our understanding of plant evolution. A growing consensus suggests that the bryophytes possibly represent three separate evolutionary lineages, which are today recognized as mosses (phylum Bryophyta), liverworts (phylum Marchantiophyta) and hornworts (phylum Anthocerotophyta). Mosses (Bryophyta) The greatest species diversity in bryophytes is found in the mosses, with estimates of the number of species ranging from 10,000 to 15,000. Higher-level classification of the mosses remains unresolved with considerable difference of opinion on the names of the major groups. However, generally four major groups or classes are recognised. These include: Sphagnopsida (peat or Sphagnum mosses), Andreaeopsida (rock or lantern mosses), Polytrichopsida (nematodontous mosses), and the Bryopsida (arthrodontous mosses). The Sphagnum mosses are one of the most ecologically and economically important groups of bryophytes. The class Bryopsida accounts for the largest and most diverse groups within the mosses with over 100 families. Liverworts (Marchantiophyta) The estimated number of liverwort species range from 6000 to 8000. Traditionally, liverworts have been subdivided into two major groups or classes based, partially, on growth form. The class Marchantiopsida, includes the well-known genera Marchantia, Monoclea, Lunularia, and Riccia, and has a complex thalloid organisation. The class Jungermanniopsida represents an estimated 85% of liverwort species and shows an enormous amount of morphological, anatomical and ecological diversity; plants with leafy shoot systems are the most common growth form in this class, e.g., Frullania, Jubulopsis, Cololejeunea, and Radula. Hornworts (Anthocerotophyta) Hornworts get their name from their long, horn-shaped sporophytes and are the smallest group of bryophytes with only approximately 100 species. Hornworts resemble some liverworts in having simple, unspecialized thalloid gametophytes, but they differ in many other characters. Hornworts differ from all other land plants in having only one large, algal-like chloroplast in each thallus cell.

Phylogeny

Scientific Name Common Name Plantae Land Plants Embryophytes Green plants

Geographic distribution

Cape Horn bryophytes

Links to other sites

Liverwort.org Botanical Society of America -- includes educational images for instructional use CalFlora Database -- California plants Introduction to the Plantae -- information about the plant kingdom Index Nominum Genericorum -- database of genera, Smithsonian Institution International Plant Names Index -- database of plant names Tropicos Database, Missouri Botanical Garden Virtual Herbarium, New York Botanical Garden Native Plants of South Texas, Texas A and M University Education Center, The Plant Health Instuctor -- American Phytopathological Society A Perspective Oriented Guide for the Identification of North American Moss Genera -- University of Illinois, Urbana, IL

Acknowledgements

This page written and compiled by: William R Buck New York Botanical Gardens, Bernard Goffinet University of Connecticut, John J Engel The Field Museum, Chicago, Matt von Konrat The Field Museum, Chicago, and John Pickering University of Georgia, Athens.

Following modified from Michael Knee, Ohio State University

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| Hort& Crop Science Home | Site Index | BRYOPHYTA The Bryophyta or mosses, unlike the liverworts, are present in most terrestrial habitats (even deserts) and may sometimes be the dominant plant life. As with the liverworts the plant that we commonly see is the gametophyte. It shows the beginnings of differentiation of stem and leaves - but no roots. Mosses may have rhizoids and these may be multicellular but they do little more than hold the plant down. The stem shows some internal differentiation into hydroids and leptoids which are like xylem and phloem of higher plants but very simply organized with no connection to leaves or branching stems. The leaves are mostly one cell thick; sometimes the midrib is several cells thick but this does not contain conducting tissue so it is not equivalent to the vein of a leaf. Male and female gametophytes look identical except when they produce reproductive structures. The male plant produces clusters of antheridia which contain thousands of ciliate sperm. The female produces archegonia, each containing a single egg. Fertilization is dependent on water - sperm are splashed or swim to the archegonia. The zygote grows into the diploid sporophyte which remains attached to the female gametophyte It is a leafless stem with a seta or foot at one end, drawing nutrients from the gametophyte. At the other end is a capsule in which meiosis occurs to form spores. The archegonium grows around the developing sporophyte for a while but becomes separated from the gametophyte and is carried up to form a cap or calyptra over the sporangium. Curiously, the sporangia of some mosses have stomata much like those on the leaves of vascular plants. Immature moss capsules with calyptra The calyptra is lost when the sporangium is mature as is the operculum or lid on the end of the capsule. Underneath the operculum there are often peristome teeth which open under dry conditions and control spore release A spore germinates to produce a filamentous protonema which sooner or later produces buds that grow into new gametophytes. Ecology of mosses Mosses require abundant water for growth and reproduction. They can tolerate dry spells by drying out or,in the case of mosses like Sphagnum , by holding huge amounts of water in dead cells in the leaves. They look pretty lowly and insignificant, but have become dominant in particular habitats and Sphagnum itself is said to occupy 1% of the earth's surface (half the area of the USA). Because of its ability to soak up blood and its relative freedom from bacterial contamination Sphagnum was used in dressings. The moss itself is used in some horticultural media and it is an important source of peat. This is a sign that I saw at a rest stop on I-90 in Wisconsin. Polytrichum commune one of the larger mosses with mature sporophytes If you have tried to grow a lawn in a shady location you have probably been troubled by mosses as weeds. Like many lower organisms they are very sensitive to copper salts and can be controlled in this way. On the other hand mosses are green and better adapted to shade than most grasses, so maybe we should accept them in this situation. QUIZ 6 | Hort& Crop Science Home | Site Index | Copyright © Michael Knee The Ohio State University All rights reserved.

Following modified from Ari Kornfeld

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Page 18 of 38 Natural Perspective The Plant Kingdom : Mosses and Allies (Last modified: 29 Sep 1997) Mosses and their allies are small green plants that are simlutaneously overlooked and deeply appreciated by the typical nature lover. On the one hand, very few people pay attention to individual moss plants and species. On the other hand, it is the mosses that imbues our forests with that wonderful lush "Rainforest" quality which soothes the soul and softens the contours of the earth. These wonderfully soft carpets of green are, in fact, Nature's second line of attack in its war against rocks. After lichens have created a foothold in rocks the mosses move in, ultimately becoming a layer of topsoil for higher plants to take root. The mosses also hold loose dirt in place, thus preventing landslides. Ecologically and structurally, mosses are closer to lichens than they are to other members of the plant kingdom. Both mosses and lichens depend upon external moisture to transport nutrients. Because of this they prefer damp places and have evolved special methods of dealing with long dry periods. Higher plants, on the other hand, have specialized organs for transporting fluid, allowing them to adapt to a wider variety of habitats. Bryophytes used to be classified as three classes of a single phylum, Bryophyta . Modern texts, however, now assign each class to its own phylum: Mosses ( Bryophyta ), Liverworts ( Hepatophyta ), and Hornworts ( Anthoceraphyta ). This reflects the current taxonomic wisdom that the Liverworts and Hornworts are more primitive and only distantly related to Mosses and other plants. Mosses (Phylum: Bryophyta ) All plants reproduce through alternating generations. Nowhere is this more apparent than in the mosses. The first generation, the gametophyte , forms the green leafy structure we ordinarily associate with moss. It produces a sperm and an egg (the gametes) which unite, when conditions are right, to grow into the next generation: the sporophyte or spore-bearing structure. The moss sporophyte is typically a capsule growing on the end of a stalk called the seta . The sporophyte contains no clorophyl of its own: it grows parasitically on its gametophyte mother. As the sporophyte dries out, the capsule release spores which will grow into a new generation of gametophytes, if they germinate. Mosses, the most common, diverse and advanced brypophytes, are categorized into three classes: Peat Mosses ( Sphagnopsida ), Granite Mosses ( Andreaopsida ), and "True" Mosses ( Bryopsida or Musci ) . Shown: Class: Bryopsida ; Order: Hypnales ; Family: Brachythecia ; Homolathecium nutalli (probably) Leafy Liverworts (Phylum: Hepatophyta , Class: Jungermanniidae ) While people typically know what a moss is, few have even heard of liverworts and hornworts. These primitive plants function much like mosses and grow in the same places, often intertwined with each other. The liverworts take on one of two general forms, comprising the two classes of liverworts: Jungermanniidea are leafy, like moss; Marchantiopsida are leaf-like ( thalloid ) similar to foliose lichens . The leafy liverworts look very much like mosses and, in fact, are difficult to tell apart when only gametophytes are present. The "leaves," however, are simpler than moss and dont have a midrib ( costa ). The stalk of the sporophyte is translucent to white; its capsule is typically black and egg-shaped. When it matures, the capsule splits open into four equal quarters, releasing the spores to the air. The liverwort sporophyte shrivels up and disappears shortly after releasing its spores. Because of this one hardly ever sees liverwort sporophytes out of season. Moss sporophtyes, on the other hand, may persist much longer. Shown: Class: Jungermanniidea ; Order: Jungermanniales ; Family: Scapaniaceae ; Scapania spp. (probably) Leaf-like Liverworts (Phylum: Hepatophyta ; Class: Marchantiopsida ) The leaf-like ( thalloid ) liverworts are, on the whole, more substantial and easier to find than their leafy counterparts. The gametophyte is flat, green and more-or-less strap-shaped. The body may, however, branch out several times to round out the form. When the gametophyte has become fertilized and is ready to produce its sporophyte generation it may grow a tall green umbrella-shaped structure called the carpocephalum . The sporophyte grows on the underside of this structure, often completely hidden from view. During the dry season, leaf-like liverworts may shrivel up and completely disappear from view until the rains arrive again. Thalloid liverworts are much easier to identify than their leafy counterparts due to the wider variety of gametophyte shapes. Shown: Class: Marchnatiopsida ; Order: Marchantiales ; Family: Aytoniaceae ; Asterella californica Hornworts (Phylum: Anthoceraphyta ) Hornworts are very similar to liverworts but differ in the shape of the sporophyte generation. Instead of generating spores in a capsule atop a stalk, the hornwort generates spores inside a green horn-like stalk. When the spores mature the stalk splits, releasing the spores. Under the microscope, hornwort cells look quite distinct as well: they have a single, large chloroplast in each cell. Other plants typically have many small chloroplasts per cell. This structure imparts a particular quality of color and translucency to the body ( thallus ) of the plant. Hornworts are all grouped into a single class, Anthocerotae , containing a single order, Anthocerotales . Shown: Class: Anthocerotae ; Order: Anthocerotales ; Family: Anthocertaceae ; Phaeoceros spp. Page 18 of 38 [ Home ] [ Contents ] [ Fungi ] [ Plantae ] [ Animalia ] [ Protoctista ] [ Species Index ] This site produced and maintained by Ari Kornfeld , email: (ari@perspective.com) Copyright © 1996-2007 All rights reserved. Please take a moment to provide your feedback on this site. Credits: Collaboration and inspiration thanks to Susan Kornfeld Early PhotoCD scans by Alpha CD Imaging , Menlo Park, CA Special thanks to Claire Doyle for scanning some early photos Internet service by Pair Networks