Paleobotany
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'''Paleobotany''', also spelled as '''palaeobotany''' (from the [[Greek language|Greek]] words ''paleon'' = old and "[[botany]]", study of plants), is the branch of [[paleontology]] or [[paleobiology]] dealing with the recovery and identification of [[plant]] remains from [[geology|geological]] contexts, and their use for the [[biological]] reconstruction of [[paleogeography|past environment]]s, and the [[evolution]] of both the [[Evolutionary history of plants|plant]] kingdom and [[Evolution of life|life]] in general. A synonym is '''paleo[[phytology]]'''. Paleobotany includes the study of [[Embryophyta|terrestrial plant]] [[fossils]], as well as the study of [[prehistoric]] [[Marine (ocean)|marine]] [[photoautotroph]]s, such as [[photosynthetic]] [[algae]], [[seaweed]]s or [[kelp]]. A closely-related field is [[palynology]], which is the study of [[fossilized]] and [[Extant taxon|extant]] [[spore]]s and [[pollen]].
Paleobotany is important in the reconstruction of ancient [[Ecology|ecological]] systems and [[climate]], known as [[paleoecology]] and [[paleoclimatology]] respectively; and is fundamental to the study of green [[Plantae|plant]] [[Developmental biology|development]] and [[evolution]]. Paleobotany has also become important to the field of [[archaeology]], primarily for the use of [[phytolith]]s in [[relative dating]] and in [[Ethnobotany|paleoethnobotany]],
==Overview of the Paleobotanical Record==
[[Macrofossil|Macroscopic remain]]s of true [[vascular plants]] are first found in the [[fossil]] record during the [[Silurian]] Period of the [[Paleozoic]] era.. Some dispersed, fragmentary fossils of disputed affinity, primarily [[spores]] and [[cuticles]], have been found in rocks from the [[Ordovician]] Period in [[Oman]], and are thought to derive from [[Marchantiophyta|liverwort]]- or [[moss]]-grade fossil plants (Wellman et al., 2003).
An important early land plant fossil locality is the [[Rhynie chert|Rhynie Chert]], an Early [[Devonian]] sinter ([[hot spring]]) deposit composed primarily of [[silica]] found outside the town of [[Rhynie]] in [[Scotland]]. [[Image:Rhynie chert.jpg|thumb|An unpolished hand sample of the Lower Devonian Rhynie Chert from Scotland.]]The Rhynie Chert is exceptional due to its preservation of several different clades of plants, from [[mosses]] and [[lycopods]] to more unusual, problematic forms. Many fossil animals, including [[arthropods]] and [[arachnids]], are also found in the Rhynie Chert, and it offers a unique window on the history of early terrestrial life.
Plant-derived [[macrofossil]]s become abundant in the Late [[Devonian]] and include [[tree]] trunks, [[frond]]s, and [[root]]s. The earliest tree is ''[[Archaeopteris]]'', which bears simple, [[fern]]-like [[leaves]] spirally arranged on branches atop a [[conifer]]-like [[trunk]] (Meyer-Berthaud et al., 1999).
Widespread [[coal]] swamp deposits across North America and Europe during the [[Carboniferous]] Period contain a wealth of fossils containing [[Lepidodendron|arborescent lycopods]] up to 30 meters tall, abundant [[Gymnosperm|seed plants]], such as [[conifers]] and [[Pteridospermatophyta|seed ferns]], and countless smaller, [[herbaceous]] plants.
[[Angiosperms]] ([[flowering plants]]) evolved during the [[Mesozoic]], and flowering plant pollen and leaves first appear during the Early [[Cretaceous]], approximately 130 million years ago.
==Plant fossils==
A [[plant]] [[fossil]] is any preserved part of a [[plant]] that has long since died. Such fossils may be prehistoric impressions that are many millions of years old, or bits of charcoal that are only a few hundred years old. Prehistoric plants are various groups of [[plant]]s that lived before recorded [[history]] (before about [[3500 BC]]).
===Kinds of plant fossils===
One of the most common kinds of plant fossils is a [[compression fossil]], in which a leaf or flattened part of the plant has been pressed between layers of sediment. Also common are fossil [[pollen]] and [[spore]]s from ancient lake beds, as well as [[charcoal]]. Less common, but economically more important, is [[coal]] from the plants of [[Carboniferous]] [[swamp]]s.
One of the most spectacular of plant fossils is [[petrified wood]].
===Form taxa===
Fossils of plants are very different from the fossils of [[animal]]s, and this is in part a result of the different architecture of plants. Animals develop with a specific parts, and in both the young and adult animal, those parts exist in fixed numbers and locations. Even animals which undergo [[metamorphosis]] have only one head, and will emerge with a fixed body structure. By contrast, plants are continually producing new branches, leaves, and other parts throughout their lives. These parts may fall off without injuring the plant. Thus, plants fossils are often fragmentary pieces such as leaves, branches, or pollen.
Since a leaf, stem, spore, or seed may be found preserved without any physical connection to the plant from which it came, [[paleobotany|paleobotanists]] use '''form taxa''' (singular '''form taxon''') to name and classify such fossils. When the true identity of such fossils is later discovered, the two form taxa may be merged. For example, in the 1960s fossil leaves called ''[[Archaeopteris]]'' (literally "ancient fern") were found attached to fossil wood of the tree ''[[Callixylon]]''. The whole plant is now known to be a [[Devonian]] tree with [[fern]]-like leaves but with [[gymnosperm]]-like [[wood]].
Some form taxa continue to exist even after their identity is determined. This is a matter of convenience for identifying quickly which part was found as a fossil, especially which the fossil may come from more than one kind of plant. Leaves assigned to the form taxon ''[[Sphenopteris]]'' come from both ferns and from seed plants; it usually is not possible to determine from isolated fossils which group the leaves belong to.
==Fossil groups of plants==
{{main|Evolutionary history of plants|List of extinct plants}}{{Cleanup-laundry|date=February 2008}}
Some plants have remained remarkedly unchanged throughout earth's geological time scale. Early [[fern]]s had developed by the [[Mississippian]], [[Pinophyta|conifers]] by the [[Pennsylvanian]]. Some plants of prehistory are the same ones around today and are thus [[living fossil]]s, such as ''[[Ginkgo|Ginkgo biloba]]'' and ''[[Sciadopitys|Sciadopitys verticillata]]''. Other plants have changed radically, or have gone extinct entirely.
A few examples of prehistoric plants are:
[[Image:Lepidostrobus variabilis.jpg|thumb|250 px|Fossil of Lepidostrobus Variabilis, a very rare scale tree cone.]]
*''[[Araucaria mirabilis]]''
*''[[Archaeopteris]]''
*''[[Calamites]]''
*[[Cycad]]s
*''[[Glossopteris]]''
*[[Horsetail]]s
*''[[Hymenaea protera]]''
*''[[Protosalvinia]]''
==See also==
* [[Evolutionary history of plants]]
* [[Timeline of plant evolution]]
* [[Prehistoric life]]
===Notable Paleobotanists===
* [[Kaspar Maria von Sternberg]] (1761–1838), the "father of paleobotany"
* [[Dunkinfield Henry Scott]] (1854-1934), analysis of the structures of fossil plants
==References==
* Brigitte Meyer-Berthaud, S.E. Scheckler, J. Wendt, "''Archaeopteris'' is the Earliest Modern Tree." ''Nature'', '''398''', 700-701 (22 April 1999) | doi:10.1038/19516
* Charles H. Wellman, Peter L. Osterloff and Uzma Mohiuddin, "Fragments of the Earliest Land Plants." ''Nature'', '''425''', 282-285 (18 September 2003) | doi: 10.1038/nature01884
*[http://waynesword.palomar.edu/ww0803.htm Jurassic Park plants] Plants that lived when dinosaurs roamed the earth.
===Further reading===
* Stewart, W.N. and Rothwell, G.W. 1993. ''Paleobotany and the evolution of plants'', Second edition. Cambridge University Press, Cambridge, UK. ISBN 0-521-38294-7
* Taylor, T. N. and E. L. Taylor. 1993. ''The Biology and Evolution of Fossil Plants'', Prentice-Hall, Inc., Englewood Cliffs, New Jersey, USA. ISBN 0-13-651589-4
==External links==
{{portalpar|Paleontology}}
* [http://www.palaeobotany.org/ International Organisation of Paleobotany]
* [http://www.dartmouth.edu/~daghlian/paleo/ Botanical Society of America - Paleobotanical Section]
* [http://www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/ebot.html Paleobotany Research Group, University Münster, Germany.]
* [http://www.abdn.ac.uk/rhynie/ The Biota of Early Terrestrial Ecosystems: The Rhynie Chert, University of Aberdeen, UK.]
* [http://paleobotany.bio.ku.edu/BiblioOfPaleo.htm Bibliography of Paleobotany]
* [http://www.univie.ac.at/sternberg/ The Sternberg Project]
* [http://www.1911encyclopedia.org/P/PA/PALAEOBOTANY.htm Paleobotany - 1911 Encyclopaedia Britannica article]
* [http://www.nhm.ac.uk/paleonet/ PaleoNet - listservs and links related to paleontology]
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