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Fossil evidence of Bryophytes Bryophyte fossil evidence are less Whatever the available material very much resembles with modern bryophytes •Plant body is simple and small in size •Plants are delicate and gametophytic •Surface of the thallus or leaf is not cuticularised •Lignified cells are not present •Vascular bundles are not present However, fossil has been recorded from tertiary beds of the paleozoic mesozoic and coenozoic era Palaeozoic era Devonian period Sporogonites exuberance •Described by Hale (1916) from lower devonian of Norway •Irregular thalloid base •Sporangiosphores bearing sporangium on a parallel line •Sporangium with a dome shaped spore sac with spores •Huber (1961) from upper devonian of New York •Earliest fossil record of hepaticae associated with fossil remains of psilotales, ferns, lycopods and gymnosperms •Prostrate rhizomatous base , erect thallus •No reproductive structures •Similar to Pallavicinia Hepaticites devonicum Carboniferous period (Walton during 1925) Hepaticites willsii •H. willsii – reported by Walton (1925) from U. Carboniferous •Ribbon shaped, dichotomously branched •Thallus with several cell layer thick in middle portion Hepaticites kidstonii •Resembles Riccia fluitans H. kidstonii – from upper carboniferous Well marked axis and two rows of lateral leaves Scale like appendage associated with each leaf Resemble Treubia in external features Upper carboniferous Hepaticites lobatus Midrib broad (axis) associated with lateral alternate lobes Appendages absent Resembles Fossombronia and Blasia Upper carboniferous Hepaticites metzgeroides Simple ribbon like, thalloid Resembles Metzgeria in external appearanceHepaticites lobatus Muscites polytrichaceous & M. burtrandi are the other fossils reported from Carboniferous period Hepaticites metzgeroides Permian Intia vermicularis Reported from Permian rocks of USSR Thallus with distinct mid rib Wings with dentate margin Mesozoic era Triassic period Naiadita lanceolata •Harris (1938) from upper triassic of England •Plant body consists of small, erect and cylindrical axis bearing spirally arranged lanceolate leaves all over •Rhizoids simple •No differentiation into conducting strand •Leaves unistratose, no midrib •Gemma like cup at the apex of the stem contains gemmae •Archegonia on the surface of the axis in extra axillary position •Archgonia have stalk and long neck •Sporophytes at the apex of the main axis consits of small foot and spherical capsule, seta absent Moss like in external appearance Sporophytes liverwort type Absence of elaters shows its nearness to the sphaerocarpales Habit, spirally arranged leaves and extra axillary archegonia - Calobyales Part of sporophyte V.S. of sporophyte Jurrasic period Ricciopsis florinii – Lundbland (1954) from Jurassic of Scania, Sweden – Resemblance with Riccia Hepaticites laevis – Harris (1931) from Jurassic of Green land – Resembles with Metzgeriales Cretaceous period Marchanites yukonensis– Hollick (1930) from Cretaceous of Yokon– Resemblance with Marchantia Jungermanitites cretaceous– Berry (1919) from Cretaceous rocks of Alabama– Resemblance with Jungermannia Muscites leguereuxi– Berry (1928) from Cretaceous of Northern America– Resemblance with Moss Coenozoic era Eocene period Marchanites stephensonii – Berry from eocene of Texas. Resemblance with Marchantia Jungermannites bryopteroides – Ball (1931) from eocene of Texas. Resembles with modern Jungermanniales Miocene period Marchanites coloradensis – Knowlton (1930) from miocene of Colorado. Showing affinity with modern Marchantiales Jungermannites cockerelli – Howe & Hollick (1922) from miocene of Colorado. Showing affinity with modern Jungermanniales Fossil bryophytes from India Capsularis gondwanensis – Saksena (1947) fossil capsule from Permo-carboniferous of Ganjra mala. It represent only a dark capsule with operculum, short seta Shuklanites deccanii –Singhai (1964) from deccan intertrappean beds of Chhindwara (M.P.) The fossil has foot, seta and capsule. Capsule has only spores and pseudoelaters but columella is absent. Showing affinity with Marchantiales and Anthocerotales Sphagnum papillosum – Vishnu Mittre & Gupta (1971) from sediments of Bhimtal, Nainital (sub fossil) Origin of bryophytes Views •Evidence from comparative morphology of the living plants •Evidence from ontogeny of the living plants •Their analogy with the living plants Two contrasting views 1. Bryophytes have descended from the pteridophytes – Pteridophytean hypothesis Supported by Scot, Lang and Kidston, Kashyap, Pande Udar etc. 2. Aquatic ancestry of bryophytes – bryophytes have evolved from algae –Algal hypothesis Supported by Bower, Fritsch, Cavers, Smith, etc Pteridophytean hypothesis •by progressive simplification or reduction •erect and leafy bryophytes like mosses are considered as primitive and they given rise to thalloid forms by progressive simplification •The sporophytes of Psilotales is simple without any differenciation into root, stem and leaves resembles with sporophytes of anthocerotales i. Close similarity between the sex organs of the two groups ii. Resemblance between sporogonium of Anthocerose, Sphagnum and Andrea and the terminal sporogonium of fossil pteridophytes – Sporogonites, Rhynia and Horneophyton Sporophytes of pteridophytes have continuous apical growth and has vascular tissue but lacking in bryophytes Pteridophytean hypothesis Affinities •Similarity of their pigments •Structure of cell wall •Food preserves •Reproductive methods •Life cycle Scott introduce the idea (1911) – presence of chlorophyll and plastids in the sporogonium of mosses and Anthoceros; Presence of stomata on the sporogonium of Anthoceros and the apophysis region of the capsule of mosses Kashyap (1919) – Liverwort have evolved from the equisetales along three independent line •Marchatiales •Jungermanniales and •Anthocerotales Christenson (1954)- bryophytes have evolved from pteridophytes possibly from •Polyphyletically, from both foliose and leafless pterodophytes •From leafless members of the family Rhyniaceae •Evolved from pteridophytes having leaves on both gametophytes and sporophytes Algal hypothesis Similarities •Amphibian nature •Presence of flagellated spermatozoid •Presence of free water at the time fertilization •Alga like protonema Lignier (1903) - Aquatic algal ancestors give rise to primitive terrestrial form such as Prohepatics Bryophtes Pteridophytes Bower (1908)- Bryophytes show resemblance with green algae (Chlorophyceae) •Photosynthetic pigments like chlorophyll α, Chlorophyll b, Carotene, leutine and violaxanthin •Starch as reserve food materials •Cellulose and pectose in the cell wall •Filamentous protonema in the juvenile stage Chlorophycean hypothesis Dilemma •Land habits of bryophytes are considered as highly advanced than the green alga •Elaborate and complex thallus •Multicellular and protected sex organs •Retention of the zygot within the venter •Production of wind disseminated spores •Heteromorphic type of alternation of generation These developmental stages are still unknown in the evolutionary run absence of the bridge species Fritsch’s view (1916, 1945) – based on comparative study of various algal groups •Gradual reduction of conductive tissue in aerial plants (as in Sargassum) •Heterotrichous habit (as in chaetophorales) •Establishment of apical growing region (as in Phaeophyscia nd Rhodophyceae) •Parenchymatous structure of erect filaments ( as in Laminariales and Fucales) Other views Church (1919) – marine algae as the ancestors of land plants instead of freshwater form Smith (1955) - bryophytes have originated from chlorophyceae – primitive form established in area having plenty of water and gradual changes from aquatic to terrestrial, this led to the establishment of more massive plant body and abundance of moisture As per Smith - Fritschiella – a member of chaetophorales may be probable nearer to the primitive ancestor for bryophytes Theory with the modern bryologists Bryophytes represent a blind ally in evolution To avoid competetion in water – group of remote ancestors of the green alga migrated to a sub aerial habitat These amphibians developed multicellular sex organs as an adaptation to a life on land From this hypothetical group both bryophytes and the primitive vascular plants evolved two parallel lines Classification Braun (1864) coined the term Bryophyta – for the group algae, fungi, lichens, and mosses Later Liverworts and mosses - Bryophyta Algae, fungi and lichens - thallophytes Schimper (1879) treated bryophyta as distinct division in plant kingdom Eichler (1883) Class - Musci Class - Hepaticae (1892) Order Sphagnales Andreales Bryales Order Marchantiales Jungermanniales Anthocerotales Bessey (1911); Fritsch (1929); Evan (1939); Engler (1954) De Barry, ex Janczewski, Leitgeb, Underwood noted the anomalous position position of Anthocerotales Howe (1899) Bryophyta Anthocerotales Hepaticae Musci Smith, Takhtajan, Wardlaw and Schuster Called anthocerotales as Anthocerotae and classes are named as Hepaticae, Anthocerotae and Musci Rothmaler (1951) Suggested the naming of class taxons Hepaticopsida Anthocerotopsida Bryopsida for Hepaticae for Anthocerotae for Musci Recognised by ICBN As per ICBN Bryophyte Hepaticopsida Liverworts Order 1. Takakiales 2. Calobyales 3. Jungermanniales 4. Metzgeriales 5. Marchantiales 6. Sphaerocarpales 7. Monocleales Anthocerotopsida Hornworts Order 1. Anthocerotales Adopted by Takhtajan (1953); Schuster (1953); Parihar (1965) and Udar (1976) ± 24000 species and 960 genera Bryopsida Mosses Sub Class 1. Sphagnidae Order – Spahagnales 2. Andreaeidae Order – Andreales 3. Buxbaumidae Order – Buxbaumiales 4. Bryidae Order – Fissidentales Dicraneales Pottiales Grimmkiales Funariales Schzostegales Tetraphidales Eubryales Isobryales Hookeriales Hypnobryales 5. Polytrichadae Order – Polytrichales Dawsoniales Hepaticopsida 330 genera; 8000 species Order Calobryales (Moss like hepatics) Jungermanniales (Scale moss hepatics) Metzgeriales (Multiform thallus) Marchantiales (Chambered hepatics Sphaerocarpales (Bottle shaped) Monocleales (Giant thallose) Based on the structure of gametophyte Anthocerotopsida 7 genera and a single order Order Anthocerotales Bryopsida 700 genera 14000 speceis Order Spahagnales Archidiales Tetraphidales Andreales Bryales Polytrichales Takakiales Based on the characters of gametophyte and sporophyte, especially peristome