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Download Introduction to Bryophytes Notes Understand: • The main groups in
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IntroductiontoBryophytes Notes Understand: • ThemaingroupsintheBryophytes • Howtodistinguishmossfromliverwort • Characteristicsofmosses • Maindiagnosticfeaturesnecessarytoidentifymossspecies • Howtousesimplemosskeys • Thenamesofatleast5mossspecies BRYOPHYTES 3groupsplants Mosses,LiverwortsandHornworts • Onlydistantlyconnectedtoeachother • Evolvedontolandbutheavilydependentonwater/moistconditions • Havethallusorsimpleleavesandstem/verythinwalls • Simple,conductingsystemfortransportingwaterandnutrients • Rhizoidsforanchorage • Sizelimitedastheycannottransportwateralongdistance/limitedtodampshady areas • Exhibitalternationofgenerationsinlifecyclewithdominantgametophyte generation ALTERNATIONOFGENERATIONS • Theleafythallusofthebryophyteishaploidandproducesgametesbymitosisand iscalledthegametophyte. • [Haploid=1setofchromosomes.Mitosis=celldivision,1celldividestoproduce2 newcells,eachwiththesamenumber,ie1set,ofchromosomes.] • Thespermatozoidsswimthroughthesurfacefilmofmoisturetoreachtheeggs • Eggsremaininsidethethallusbutopentotheoutsideviapores. • Thespermatozoidsareattractedtochemicalssecretedbytheegg • Theresultoffertilisationisadiploidzygotewhichgrowsintoadiploidplant • [Onemalehaploidgamete(aspermatozoid)joinswithonefemalehaploidgamete (egg).Thefertilisedegg(zygote)nowhas2setsofchromosomes,soisdiploid.] • Thisproducessporesbymeiosisandiscalledthesporophyte. • [Meiosis=divisionofadiploidcellwhichproducesnewcellsthathaveonly1setof chromosomes,iehaploidcells.] • Thesporophyteremainsattachedtotheparentgametophyte COMPARISONACROCARPSANDPLEAUROCARPS AcrocarpsPleurocarps • Erectgrowthform,nonbranchedSpreading,branchedhabit • MostleaveswithnerveLeaveswithorwithoutanerve • Sporophytes/fruitingbodiesSporophytes/fruitingbodies terminalatapexsteminaxilsofstem ComparisonMossesandLeadyliverworts MossesLeafyLiverworts LeavesspirallyarrangedupstemLeavesin2or3ranksalongstem LeavesunlobedLeavesunlobedorlobed LeavesoftenhaveanerveLeavesneverhaveanerve SporophytepersistentSporophyteshort-lived SpeciesListforNov1st 1. Thuidiumtamariscinum 2. Pseudoscleropodiumpurum 3. Atrichumundulatum 4. Mniumhornum 5. Eurynchiumstriatum 6. Hypnumcupressiforme 7. Rhytidiadelphussquarrosus 8. R.triquetris 9. Pleuroziumschreiberi 10. Aulocomniumpalustre 11. Plagiotheciumsp 12. Kindbergiapraelonga 13. Polytrichumcommune 14. Hylocomiumsplendens 15. Fissidenssp 16. Ctenidiummolluscum L1ThalloseliverwortPellia L2ThalloseliverwortConocephalum
