Bulletin of geosciences | |
Review of the wood anatomy of extant Ulmaceae as context for new reports of late Eocene Ulmus woods | |
Manchester SR1  Wheeler EA1  | |
关键词: Ulmaceae; Ulmus; Eocene; fossil wood; wood anatomy; John Day Formation; | |
DOI : | |
来源: Czech Geological Survey | |
【 摘 要 】
WoodanatomyofextantUlmaceaeisbrieflyreviewedtoprovidecontextfordescriptionsofcorrespondingfossilwoods,withattentiontonewlyrecognizedwoodsfromthelateEoceneofOregon,USA.Theextantgeneracanbedistinguishedfromoneanotherusingporositytype,presenceorabsenceofvesselclusters,axialparenchymatype,raywidth,andcrystaloccurrence.ThelateEocenewoodsfromPost,Oregon,conformanatomicallywiththoseofextantUlmus.Toassesswhetherfossilwoodsmightbeidentifiedtoaninfragenericcategory,selectedwoodanatomicalfeaturesof21extantspeciesofUlmusaresummarizedtoevaluatewhetheranysectionswithinthegenushavedistinctiveanatomy.PorositytypeinextantUlmusisrelatedtoleaflongevity;extantevergreenspeciesarediffuseporousandhaverelativelynarrowrays.OtherextantUlmusspeciesaredeciduousandpredominantlyringporous,onlyrarelysemi-ringporous,withclusteredlatewoodvesselsthataretangentiallyarranged.Sometimesearlywoodcharacteristicshavesystematicvalueandallowrecognitionofgroups.However,insomespeciesearlywoodcharacteristicsarevariable,apparentlybeingmuchaffectedbygrowingconditions.EasternU.S.speciesbelongingtoSectionsChaetopteleaandTrichopteleaofSubgenusOreopteleaconsistentlyhavethick-walledfibers,singlerowsofsmall-mediumdiameterearlywoodvessels,andlittledifferencebetweenthediametersofthesolitaryearlywoodvesselsandlatewoodvessels.ThelateEoceneUlmuswoodiisp.nov.sharesmorefeatureswiththisgroupthananyother.AnotheroftheselatePostEocenewoodsisreferabletoUlmusdanielii,aspeciespreviouslyknownonlyfromtheMiddleEoceneClarnoFormation.AthirdfossilwoodtyperesemblesdiffuseporousUlmus,butitslowerpreservationalqualityobscuressomediagnosticfeaturesandprecludessecureassignment.
【 授权许可】
Unknown
【 预 览 】
Files | Size | Format | View |
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RO201912090782979ZK.pdf | 1225KB | download |