Review of the wood anatomy of extant Ulmaceae as context for new reports of late Eocene Ulmus woods

Bulletin of geosciences

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