Bryophyte Talk JLA...This process contributes to the formation of gemmae and brood bodies. Brood bodies – Small vegetative, plant‐like diaspores produced in leaf axils by mosses.

“Bryophytes” Are

Mosses, Liverworts, and Hornworts

Bryophytes were once known as Class Musci, Class Hepaticae, and Class Anthocerotae, but are now elevated to Phylum Bryophyta, Phylum Marchantiophyta, and Phylum Anthocerotophyta.

Important Defining Characteristics of the Three Groups*

Structure\Group Mosses Liverworts Hornworts

Vegetative/Gametophyte (n)

Protonema Well‐developed/cross‐walls oblique

Reduced Sporeling

Gametophore Leafy Leafy or Thallose Thallose

Phyllotaxy Radial 3‐5 2‐3 on leafy species Absent

Leaves/stem relationship

Separate Separate and incubous (T/B), succubous (B/T) or absent from thallose species

Absent

Costa Single, double or absent

Absent Absent

Leaf Cells Multiple leaf cell shapes

Cells isodiametric in leafy liverworts

Some specialization of thallus cell types

Oil bodies Small or absent Well developed Starch Pyrenoids

Rhizoids Multicellular/brown, sometimes papillose

Unicellular, not branched

Unicellular, smooth, colorless

Vegetative Reproduction

Gemmae, brood bodies, fragmentation

Gemmae, fragmentation

Tubers in and gemmae on some thalli

Reproductive/Sporophyte (2n)

Antheridia On leafy stems On leafy stems and thallus tissue

In thallus tissue

Archegonia On leafy stems On leafy branches and thallus tissue

In thallus tissue

Calyptra Expanded/ripped part of venter enclosing egg

Shoot‐calyptra at least in part

Absent

Dry Capsule Present Sporangium Sporangium

Operculum Present Absent Absent

Perianth Absent—perichaetium on gametophyte

Present in leafy species; otherwise, involucre

Involucre

Peristome Present Absent, Elaters Absent, Elaters

Seta Photosynthetic, rigid Rarely photosynthetic Absent

Spore dispersal Capsule dries and forces spores into peristome which flip spores out

4 lines on sporangium split jacket and elaters lose moisture

Sporangium ruptures by 1 or 2 longitudinal lines; elaters usually present

Stomata on sporophyte Usually present Absent Usually present

*Red means that the structures may be visible with hand lens or unaided eye.

2 Bryophytes of North Carolina ‐ http://dpr.ncparks.gov/bryophytes/index.html NC Biodiversity Project ‐ http://nc‐biodiversity.com NCBP Workshop April 2019, DuMond & Amoroso

Generalized Bryophyte Life Cycle

Spore tetrads of Riccia sorocarpa, a thallose liverwort


Glossary of Important Words for the Bryophyte Language

The following definitions come from words used in the current handout. It is in all other respects incomplete. Many of the references listed on the Bryophytes of North Carolina web page located at: https://auth1.dpr.ncparks.gov/bryophytes/reference.php contain glossaries that are much more inclusive.

Acrocarpous – Usually said of mosses which produce sporophytes from the tip of the main stem. See pleurocarpous. Most such mosses are sparingly branched and more or less erect, often forming tufts. It is a general term that can be difficult to apply due to exceptional cases. Mosses exhibiting this habit are often referred to as acrocarps. Antheridial head – A terminal cluster of male reproductive organs and associated structures, particularly on mosses. Antheridophore ‐‐ A male gametangial structure which bears antheridia. These are characteristic of thallose liverworts. Antheridium (antheridia‐plural) – Male reproductive organ which releases motile sperm. Anthocerotae – An outdated term for the taxonomic Class of organisms which included hornworts. Anthocerotophyta – Name of the Phylum (or Division) of organisms which currently includes hornworts. Archegonium (archegonia‐plural) – Female reproductive structure in which egg forms, in which fertilization takes place and which contributes to formation of calyptra. Archegoniophore – A female gametangial structure which bears archegonia. These structures are most characteristic of thallose liverworts. Asexual reproduction – reproduction by mitosis only without the process of meiosis (reduction /division). This process contributes to the formation of gemmae and brood bodies. Brood bodies – Small vegetative, plant‐like diaspores produced in leaf axils by mosses. Bryophyta – Name of the Phylum (Division) of organisms which currently includes mosses. Bryophytes – Common name often used to include mosses, liverworts and hornworts. Calyptera (calyptrae‐plural) – Structure carried upward or outward at the tip of the developing sporophyte and originating from tearing of archegonial venter (part enclosing egg) during capsule and seta growth. The calyptra continues growth in step with the capsule maturation, provides protection for the developing capsule and is shed at or about the time of capsule maturity. Capsule – Sporangial portion of the moss sporophyte in which haploid spores are produced. Class – A taxon (group name) used in taxonomic classification.


Classification – Process of assigning or organizing biological entities into taxa or hierarchical groups. Includes ordering of taxa within such as Kingdom, Phylum (Division), Class, Order, Family, Genus, Species, Subspecies, Variety, etc. Conducting parenchyma – A generalized cell or tissue type that allows movement of water through its cell walls and, hence, through a plant. See Costa. Costa (costae‐plural) – Mid‐rib that includes a central strand or strands of a moss leaf that often include tissue known as stereid cell bands (stereids) which function in support of the plant and guide cells (deuters) which may function in storage. These are sometimes closely associated, in some mosses, with cell types that function in water transport (hydroids and conducting paranchyma) and photosynthetic material transport (leptoids). Research is on‐going regarding the analagous or homolagous nature of these cell types to fibers, tracheids and sieve elements present in woody and herbaceous vascular plant tissues. Cross wall – The end cellulose partitions separating adjacent cells of a linear arrangement; as in rhizoids and protonema. Plant cells have walls are usually composed of cellulose while animal cells have phospholipid‐protein membranes. Diaspore – Plant structure that serves as a dispersal unit. Dichotomous branching – A terminal branching pattern common in the plant world by which branching of a stem always produces two equal branches. Many thallose liverworts demonstrate dichotomous branching. Dioicous – A gametophyte that regularly produces only archegonia or antheridia, not both. See monoicous. Not to be confused with dioecious in which flowering plants bear male and female flowers on separate plants. Diploid – A condition in which an organism has two complete sets of chromosomes. See haploid. Dispersal – Movement or transportation through action of some agent or vector, such as wind, water, an animal, etc. Dorsal – Especially in liverworts, the top or portion of a plant most likely open to light. Elaters – Cellular products of meiosis that develop into hydroscopic coils and change shape rapidly with changes in humidity in the opening sporangia of liverworts and hornworts, thus assisting in dispersal of spores. Fertilization – The union of sperm and egg or syngamy. Flagellum (plural flagella) – One of two fine hair‐like structures employed for mobility by male gametes. Fragmentation – Loss or casting of small irregular pieces of gametophytic tissue that may function in plant transport and propagation. Gametangia (gametangium‐singular) –Gamete‐producing structures, archegonia or antheridia.


Gamete – A haploid sexual cell specialized for fertilization or syngamy. Gametophore ‐‐ A haploid bryophytic plant that produces gametangia. Gametophyte – A haploid plant or part of a set of haploid plant structures. Gemma (plural‐gemmae) – A cell or group of cells specialized for dispersal as a vegetative or asexual reproductive unit. Haploid – A condition in which an organism has only one complete set of chromosomes. See diploid. Hepaticae – An outdated term for the taxonomic Class of organisms which included liverworts. Hornwort – Members of Phylum (Division) Anthocerotophyta. Hydroid – Cell type in some mosses that is specialized for water transport. Hydrom (or Hydrome) –Tissue type in some mosses that is specialized in water transport. Incubous – Leaf position in leafy liverworts in which the top of a leaf overlaps the bottom of the leaf just above as viewed from the dorsal side of the plant. Involucre – A tissue enclosure around the base of sporophytes of some liverworts and hornworts. Jacket – Term sometimes applied to the tough outermost wall of a capsule. Leptoid – Cell type in stems and costae that functions in transport of the products of photosynthesis. Leptom (or Leptome) – Tissue with leptoid cell types. Lipids – Oils used in plant metabolic processes. Liverwort – Member of the Phylum (Division) Marchantiophyta. Marchantiophyta – Phylum or Division that includes liverworts. Meiosis – A form of cell division that includes both a reduction of ploidy states (from 2n to n) and cell division resulting in a group or tetrad of four haploid cells. Mitosis – Cell division. Monoicous – A gametophyte that regularly produces both archegonia or antheridia. See dioicous. Not to be confused with monoecious that describes the condition where flowering plants bear male and female flowers on a single. Moss – Member of the Phylum or Division Bryophyta. Motile – Able to move, usually by use of flagella.


Musci – An outdated term for the taxonomic Class which included mosses. Oil bodies – Cellular inclusions specializing in storage of lipids. Operculum (opercula‐plural) – Lid of capsule resembling a cap and usually, in mosses, found under the calyptra. Papillose – Roughened or thickened by papillae. Papillae (papilla‐singular) – microscopic protuberances on the outside surface of a cell wall. Perianth – Structure found on leafy liverworts that may consist of fused leaves and that surround and protect the developing sporophyte. Not to be confused with the whorls of sepals, petals and nectaries subtending anthers in flowering plants. Perichaetial leaves– Specialized gametophytic leaves surrounding the base of the sporophyte in mosses. The perigonium (‐a, plural) surrounds antheridia in male gametophores, and the perichaetium (‐a, plural) surrounds female gametophores, and, ultimately sporophytes. Peristome – Set of 4‐‐16 hydroscopic structures arising from within the mouth of the capsule which function in spore dispersal. These teeth are covered by the operculum prior to drying of the capsule. Photosynthetic – Term applied to structures or cells containing chlorophyll and capable of producing sugars used in plant metabolism. Phyllotaxy – Leaf arrangement around a stem as pertains to the number of leaves arising within one spiral turn along the stem. Phylum (or Division) – Classification level below Kingdom, that includes all classes. Phylum Bryophyta, Phylum Marchantiophyta, and Phylum Anthocerotophyta. Pleurocarpous – Said of mosses which produce sporophytes from sides of main or lateral stems. Such mosses are usually prostrate and branched. It is a general term that can be difficult to apply due to exceptional cases. Mosses exhibiting this habit are often referred to as pleurocarps. Ploidy state – Any of several integers used to refer to the numbers of chromosome groups present in cells of a group of organisms. Protonema (protonemata‐plural) – An accumulation of often photosynthetic (chloronema) cells that form a preliminary tissue which initiate continued development of gametophore. The youngest stage of growth of the gametophyte, in mosses, often resembling algae. Pyrenoid – Cellular structures specialized in manufacture of starch. Radial – A type of arrangement of structures progressing from the center of the plant to the edge, or the reverse, as in radial symmetry. Reduction/division – Two types of cell division that occur during the process of meiosis.


Rhizoid – Usually linear, fine structures specialized in gathering moisture and providing support and attachment to a substrate. Seta – Stem of capsule and portion of the sporophyte most responsible for growth away from the gametophyte of mosses and liverworts. Sexual reproduction –A form of cell division that results in meiosis and the production of haploid gametes. Shoot‐calyptra – Formation of a calyptra‐like structure in liverworts that is dissimilar from the moss calyptra. Species – A distinct group of organisms with a shared evolutionary trajectory. Sperm – Male gamete. Sporangium (sporangia‐plural) – Structure supporting the process of meiosis and growth and development of spores. Spore – First cell of the haploid generation. Sporeling – Early protonema‐like tissue in liverworts and hornworts following spore germination. Sporophyte – Physiologically and physically dependent individual of the bryophyte diploid generation. Stem – Supporting structure connecting plants to a substrate. Stomata (singular‐stoma) – specialized openings for controlling passage of moisture and gasses often associated with moss and hornwort sporophytes. Substrate – A medium supporting bryophyte attachment. Succubous – Leaf arrangement in leafy liverworts in which the bottom of a leaf overlaps the top of the leaf below. See incubous. Syngamy – union of gametes; fertilization. Tetrad – Group of four spores resulting from meiosis. Thalloid – Flat, closely appressed to substrate. Thallose ‐‐ Flat, ribbon like and closely appressed to substrate. Thallus (thalli‐plural) – A plant body and, additionally, one that may be thallose or one that is flat, ribbon like and closely appressed to substrate. Tuber – A vegetative reproductive, perennating structure imbedded in the thallus tissue of hornworts. Unicellular – Consisting of one spore.


Vegetative reproduction – Reproduction without meiosis. Venter – Portion of archegonium around egg. Ventral – Often used with liverworts to refer to that portion of the plant not exposed to light; the under part. Zygote – Fertilized egg. First cell of the diploid generation.

Pictures of a few common bryophytes

A Hornwort: Phaeoceros carolinianus


A Liverwort: Conocephalum salebrosum

A Liverwort: Bazzania trilobata


A Moss: Funaria hygrometrica

Mosses: Sphagnum palustre and Thuidium delicautlum (the small one that looks like a tiny fern).

Bryophyte Talk JLA...This process contributes to the formation of gemmae and brood bodies. Brood bodies – Small vegetative, plant‐like diaspores produced in leaf axils by mosses.

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