Focused on Palaeoclimate
Tree-Ring Research (Dendrochronology) in General
The Pros and Cons of Pre-Neogene Growth Rings
Leaf Size and Shape and the Reconstruction of Past Climates
The Rise of Oxygen and the Global Carbon Cycle
Teaching Documents about Plant Anatomy@
Teaching Documents about Botany@
Permineralized Plants and Petrified Forests@
Teaching Documents about Palaeoclimate@
! Abscission and Tissue Separation in Fossil and Extant Plants@
Teaching Documents about Palaeobotany@
Karsten Alfermann (2001): Untersuchungen zur Anpassung des Photosyntheseapparates Höherer Pflanzen bei Wachstum unter einem erhöhtem CO2-Partialdruck von 700 ppm. PDF file (9.3 MB), in German. Dissertation, Universität Bielefeld.
R. Barclay, J. McElwain, D. Dilcher and B. Sageman (2007): The cuticle database: developing an interactive tool for taxonomic and paleoenvironmental study of the fossil cuticle record. PDF file, In: Jarzen, D. M., Steven, R., Retallack, G. J. and Jarzen, S. A. (eds.), Advances in Angiosperm Paleobotany and Paleoclimatic Reconstruction, Contributions Honouring David L. Dilcher and Jack A. Wolfe, Courier Forschungsinstitut Senckenberg, Frankfurt, pgs. 39-56.
Paul Beaumont, Science and Plants for Schools, Homerton College, Cambridge, UK: How do I measure stomatal density?
D.J. Beerling et al. (1998): Stomatal responses of the "living fossil" Ginkgo biloba L. to changes in atmospheric CO2 concentrations. PDF file, Journal of Experimental Botany, 49: 1603-1607.
White Rose Palaeobiology Group, UK:
Atmospheric CO2 and climate change during the Permo-Carboniferous glaciation inferred from
fossil plants. Project description. See also
(Low atmospheric CO2 levels during the Permo-
Carboniferous glaciation inferred from
fossil lycopsidsPDF file, in PDF).
These expired links are available through the Internet Archive´s Wayback Machine.
Beerling DJ, Lake JA, Berner RA, Hickey LJ, Taylor DW, Royer DL. 2002:
Carbon isotope evidence implying high O2/CO2 ratios
in the Permo-Carboniferous atmosphere.
PDF file, from Geochimica et Cosmochimica Acta, 66: 3757-3767.
Snapshot taken by the Internet Archive´s Wayback Machine.
D. J. Beerling, B. H. Lomax, D. L. Royer, G. R. Upchurch, Jr., and L. R. Kump: An atmospheric pCO2 reconstruction across the Cretaceous-Tertiary boundary from leaf megafossils. The National Academy of Sciences, PNAS 2002 99: 7836-7840.
D. J. Beerling Department of Animal and Plant Sciences, University of Sheffield, and D. L. Royer,
Department of Geology and Geophysics, Yale University, New Haven:
Reading a CO2 signal from fossil stomata.
Research review, PDF file (New Phytologist, 2002; 153: 387– 397).
This expired link is available through the Internet Archive´s Wayback Machine.
Robert A. Berner, Geology and Geophysics, Yale University, New Haven, Connecticut: The Rise of Plants and Their Effect on Weathering and Atmospheric CO2 (now via wayback archive). See also here, and there.
Robert A. Berner, Department of Geology and Geophysics, Yale University, New Haven, CT: Atmospheric oxygen over Phanerozoic time. PNAS, Vol. 96, Issue 20, 10955-10957, September 28, 1999.
! J.A. Berry et al. (2010): Stomata: key players in the earth system, past and present. Abstract, Current opinion in plant biology, 13: 232–239. See also here (in PDF).
Bert Bolin, Egon T. Degens, Stephan Kempe, and Pieter Ketner 1979 (illustrated HTML at icsu-scope.org,
The Scientific Committee On Problems of the Environment):
Global Carbon Cycle. This expired link
is available through the Internet Archive´s
For instance: The Possible Effects of Increased CO2 on Photosynthesis. by J. Goudriaan and Jr. G. L. Ajtay.
! Nina R. Bonis (2010), Laboratory of Palaeobotany and Palynology,
Palaeoecology Institute of Environmental Biology,
Department of Biology, Utrecht University:
and vegetation history during the Triassic-Jurassic transition.
PDF file (7.7 MB), LPP Contribution Series No. 29. Seven research reports (chapters)
in this thesis, see especially chapter 7 (with W.M. Kürschner):
! Vegetation history, diversity patterns, and climate change across the Triassic-Jurassic boundary (PDF page 140).
Tim J. Brodribb et al. (2007): Leaf Maximum Photosynthetic Rate and Venation Are Linked by Hydraulics. PDF file, Plant Physiology, 144: 1890-1898.
Steve Case, University of Kansas Lawrence (page hosted by Access Excellence): Leaf Stomata as Bioindicators of Environmental Change.
! Center for the Study of Carbon Dioxide and Global Change:
Are Physical Properties of Stomata
Unresponsive to CO2?
Provided by the Internet Archive´s Wayback Machine.
Stomatal density (SD; the number of stomata per unit leaf area) and stomatal index (SI; the number of stomata divided by the sum of the numbers of stomatal and epidermal cells) are often used as proxies of past atmospheric CO2 concentrations. The evidence for the validity of this technique is said by Reid et al. to rest primarily upon paleontological data and growth chamber studies. Hence, they sought to broaden the experimental basis for the protocol by adding field studies to the mix of evidence supporting it.
! Center for the Study of Carbon Dioxide and Global Change, Tempe, AZ.
This center was created to disseminate
factual reports and sound commentary on new developments in the world-wide scientific quest
to determine the climatic and biological consequences of
the ongoing rise in the air's CO2 content. Go to:
Stomatal Density. Directory of articles, e.g.
Stomatal Frequency Responses of Conifer Needles to
Atmospheric CO2 Enrichment.
These expired links are available through the Internet Archive´s Wayback Machine.
CLAMP Online (Climate Leaf Analysis Multivarite Program).
This site is the result of an ongoing collaboration between the Institute of Botany, Chinese Academy of Sciences, Beijing,
and the Open University UK.
How you can use foliar physiognomy (leaf architecture) to determine ancient climates from fossil leaves or explore the relationship that exists between leaf form and climate. CLAMP is a multivariate statistical technique that decodes the climatic signal inherent in the physiognomy of leaves of woody dicotyledonous plants. See especially:
! Teaching Materials.
Older CLAMP websites are available through the Internet Archive´s Wayback Machine:
Robert A. Spicer, The Warm Earth Environmental Systems Research Group: Plant Fossils as Climatic Indicators. Go to: Climate Leaf Analysis Multivariate Programe (CLAMP). An introduction to the use of leaf architecture for determining past climatic conditions.
Tom Clarke, Nature scienceupdate, 17 May 2001:
Climatologists pore over past.
Fossil leaves tell us about the air the dinosaurs breathed.
Still provided by the Internet Archive´s Wayback Machine.
Richard Crang, University of Illinois at Urbana-Champaign, Andrey Vassilyev, St. Petersburg State University, Russia (McGraw-Hill Higher Education): Plant Anatomy. A website that supports the Electronic Plant Anatomy CD-ROM. An instructor view provides links to dynamic cartoons viewable using the Macromedia Flash Player. Go to: "Stomata" (opening and closing stomata), and "Leaf Structure".
Judith L. Croxdale, Department of Botany, University of Wisconsin, Madison (website hosted by Biology Online):
patterning in angiosperms.
Stomatal pattern types, means of measuring them, advantages of each type of measurement, and then present patterning from evolutionary,
physiological, ecological, and organ views are discussed.
Website outdated, a version archived by the Internet Archive Wayback Machine.
! D.L. Dilcher (1974): Approaches to the identification of angiosperm leaf remains. In PDF, The Botanical Review, 40: 1–157. See also here.
Plant Palaeoecology and Palaeobiology Group, Dublin, Ireland:
OXYEVOL: The role of atmospheric oxygen in plant evolution over the past 400 million years.
The aim of the project is to identify how changes in atmospheric O2 and CO2 concentration influence the timing of key evolutionary innovations and shifts in ecological dominance/success of various plant groups throughout geological time.
R.G. Daly and R.A. Gastaldo (2010): The effect of leaf orientation to sunlight on stomatal parameters of Quercus rubra around the Belgrade Lakes, central Maine. PDF file, Palaios, 25: 339-346.
C. Elliott-Kingston et al. (2016): Does size matter? Atmospheric CO2 may be a stronger driver of stomatal closing rate than stomatal size in taxa that diversified under low CO2. In PDF, Front Plant Sci., 7. See also here and there.
C. Elliott-Kingston et al. (2014): Damage structures in leaf epidermis and cuticle as an indicator of elevated atmospheric sulphur dioxide in early Mesozoic floras. In PDF, Review of Palaeobotany and Palynology, 208: 25-42.
Encyclopedia of Earth. An electronic reference about the Earth, its natural environments, and their interaction with society. Go to: What are stomata? About stomatal density, size and shape, physiological function of stomata, optimal size of stomatal apertures, and stomatal conductance. More botany articles here, and there (all titles A-Z).
A. Fangmeier & H.-J. Jäger, Institut für Pflanzenökologie der Justus-Liebig-Universität Gießen: 4.2 Wirkungen erhöhter CO2-Konzentrationen. PDF file (in German), from Guderian, R. (ed.): Handbuch der Umweltveränderungen und Ökotoxikologie; Band 2a: Terrestrische Ökosysteme. Berlin: Springer, 2001.
Ben Fletcher, Department of Animal and Plant Sciences, University of Sheffield: How the atmosphere affects plants. See also: The role of stomata in the early evolution of land plants.
P.J. Franks et al. (2012): Megacycles of atmospheric carbon dioxide concentration correlate with fossil plant genome size. In PDF, Phil. Trans. R. Soc. B, 367: 556-564.
! Peter J. Franks and David J. Beerling (2009): Maximum leaf conductance driven by CO2 effects on stomatal size and density over geologic time. PDF file, PNAS, 106: 10343-10347.
! Robert A. Gastaldo, Department of Geology, Colby College, Waterville, Maine: PLANTS AS KEYS TO PAST CLIMATIC CONDITIONS. Plants are independent data set to test climate hypotheses. They are spatially-fixed adapted to atmospheric and substrate conditions. They are tightly constrained by the climatic regime under which they grow. See also Is it possible to retrodict? Fossils as environmental indicators.
Bruce W. Grant and Itzick Vatnick, Teaching Issues and Experiments in Ecology (TIEE). This is a project of the Education and Human Resources Committee of the Ecological Society of America: Environmental Correlates of Leaf Stomata Density. The technique of making clear nail polish impressions of leaf stomata.
! David R. Greenwood, Environmental Science Program, Brandon University, Brandon, Manitoba, Canada: Fossil plants as environmental indicators. Lecture note, PDF file (3.6 MB). Provided by the Internet Archive´s Wayback Machine.
M. Haworth et al. (2011): Stomatal control as a driver of plant evolution. In PDF, J. Exp. Bot., 62: 2419-2423.
M. Haworth et al. (2011): Cycads show no stomatal-density and index response to elevated carbon dioxide and subambient oxygen. Abstract, Australian Journal of Botany.
Matthew Haworth et al. (2010): Differences in the response sensitivity of stomatal index to atmospheric CO2 among four genera of Cupressaceae conifers. PDF file, Ann. Bot., 105: 411-418.
A.M. Hetherington and I. Woodward: The role of stomata in sensing and driving environmental change. Abstract, Nature 424, 901 - 908 (21 August 2003).
The Hindu, India: Fossil leaves reveal Earth's history.
R.A. Houghton, Woods Hole Research Center,MA: The Contemporary Carbon Cycle. (PDF file). A sample chapter of Volume 8. Biogeochemistry (William H. Schlesinger), Treatise on Geochemistry.
Kevin R. Hultine (Department of Forest Resources, University of Idaho, Moscow, ID), and John D. Marshall (website hosted by Biology Online): A comparison of three methods for determining the stomatal density of pine needles. Three methods used to estimate the stomatal density of two species of three-needle pines, Pinus taeda and Pinus ponderosa is reported.
! G.J. Jordan et al. (2015): Environmental adaptation in stomatal size independent of the effects of genome size. In PDF, New Phytologist, 205: 608-617.
P. Kenrick (2001): Turning over a new leaf. PDF file, Nature, 410: 309-310. This expired link is available through the Internet Archive´s Wayback Machine.
Richard A. Kerr, Science magazine, April 2005: Gasping for Air in the Permian. Thin air may have forced animals down from higher latitudes 250 million years ago, crowding them into the lowlands and possibly helping along the largest extinction in the history of the planet, according to a study of Science.
Hans Kerp, Forschungsstelle für Paläobotanik, Geologisch-Paläontologisches Institut, Westfälische Wilhelms-Universität, Münster, Germany: Palaeobotany (Communications arising): Atmospheric CO2 from fossil plant cuticles. Abstract, Nature 415, 38 (2002). See also here
John W. Kimball, Kimball´s Biology Pages: Gas Exchange in Plants.
Lenny L.R. Kouwenberg et al. (2007): Stomatal Frequency Change Over Altitudinal Gradients: Prospects for Paleoaltimetry. PDF file, Reviews in Mineralogy & Geochemistry, 66: 215-241.
Lenny L.R. Kouwenberg et al. (2005): Atmospheric CO2 fluctuations during the last millennium reconstructed by stomatal frequency analysis of Tsuga heterophylla needles. PDF file, Geology, 33: 33-36.
Wolfram M. Kürschner, Laboratory of Palaeobotany and Palynology, Utrecht University: Leaf sensor for CO2 in deep time. News and views, Nature 411, 247 - 248 (2001).
Wolfram M. Kürschner, Johan van der Burgh, Henk Visscher, and David L. Dilcher: Oak leaves as biosensors of late Neogene and early Pleistocene paleoatmospheric CO2 concentrations. Abstract.
U. Kutschera (2008): The growing outer epidermal wall: Design and physiological role of a composite structure. PDF file, Ann. Bot. 101: 615-621.
U. Kutschera and K.J. Niklas (2007): The epidermal-growth-control theory of stem elongation: An old and a new perspective. PDF file, J. Plant Physiol. 164: 1395-1409.
! A.D.B. Leakey and J.A. Lau (2012): Evolutionary context for understanding and manipulating plant responses to past, present and future atmospheric [CO2]. Phil. Trans. R. Soc. B, 367: 613-629. See als here (in PDF).
B.H. Lomax and W.T. Fraser (2015): Palaeoproxies: botanical monitors and recorders of atmospheric change. In PDF, Palaeontology. See also here (abstract).
B.H. Lomax et al. (2013): Reconstructing relative genome size of vascular plants through geological time. In PDF, New Phytologist.
! J. Loranger and B. Shipley (2010): Interspecific covariation between stomatal density and other functional leaf traits in a local flora. PDF file, Botany, 88: 30-38.
! J.C. McElwain et al. (2016): Was atmospheric CO2 capped at 1000 ppm over the past 300 million years? In PDF, Palaeogeography, Palaeoclimatology, Palaeoecology, 441: 653–658. See also here.
! J.C McElwain et al. (2015): Using modern plant trait relationships between observed and theoretical maximum stomatal conductance and vein density to examine patterns of plant macroevolution. New Phytologist, 209: 94-103.
Jennifer C. McElwain, UCD Earth Systems Institute, Dublin:
Climate change and mass extinction: What
can we learn from 200 million year old
Provided by the Internet Archive´s Wayback Machine.
Jennifer C. McElwain, Department of Geology, The Field Museum, Chicago: A novel climate-independent method for estimating paleo-elevation from fossil plants. Abstract; Botany 2001 "Plants and People" August 12 - 16, 2001, Albuquerque.
! J.C. McElwain and W.G. Chaloner (1995): Stomatal density and index of fossil plants track atmospheric carbon dioxide in the Palaeozoic. PDF file, Annals of Botany, 76: 389-395.
! Jennifer C. McElwain and William G. Chaloner, Department of Biology, Royal Holloway, University of London, Egham: The fossil cuticle as a skeletal record of environmental change. PDF file, see also here (Abstract), and there.
Jennifer C. McElwain, Jessica Wade-Murphy and Stephen P. Hesselbo: Changes in carbon dioxide during an oceanic anoxic event linked to intrusion into Gondwana coals. Abstract, Nature 435: 479-482; May 2005. Using the stomatal index method. Although multiple forcing factors may have contributed to the abrupt spike in atmospheric CO2, the authors suggest that the likely dominant forcing factor was oxidation of methane gas generated by subsurface thermal metamorphism of organic-rich late Permian and late Triassic coal bearing strata during magmatic intrusion of the Karoo-Ferrar large igneous province of southern Gondwana.
mysan.de/international (a Montrasio and Illing GdbR News Portal): Holy Grail of Geology Found: Measuring Elevation Over Geological Eras. New method (counting the stomata on leaves of fossil plants) to measure ancient land elevation developed by Field Museum scientist. See also here (Der Spiegel, in German).
Nature Highlights: Evolution: Extinct theories? About the stability of atmospheric CO2 levels across the Triassic/Jurassic boundary (Tanner et al. 2001).
New Phytologist, Forum: Remote control – cell and organ communication within plants. PDF file.
Larry O'Hanlon, Discovery News: Ancient Fossil Fuels Caused Jurassic Warming. The carbon dioxide level and the stomata method. Provided by the Internet Archive´s Wayback Machine.
Larry Orr, Photosynthesis Center, Arizona State University, Tempe, AZ: What is Photosynthesis? Links (with annotations) to articles that discuss photosynthesis at varying degrees of complexity.
C.P. Osborne et al.(2004):
constraints on the origin of leaves inferred from the fossil record.
PDF file, PNAS, 101: 10360-10362.
This expired link is available through the Internet Archive´s Wayback Machine.
Osborne, C.P. & Beerling, D.J. (2002): A process-based model of conifer structure and function with special emphasis on leaf lifespan.. Global Biogeochemical Cycles.
J.L. Payne et al. (2006): The Pattern and Timing of Biotic Recovery from the End-Permian Extinction on the Great Bank of Guizhou, Guizhou Province, China. In PDF, Palaios, 21: 63-85.
! N. Pérez-Harguindeguy et al. (2013): New handbook for standardised measurement of plant functional traits worldwide. In PDF, Australian Journal of Botany, 61: 167-234.
Sara Pratt, Geotimes: Reaching past heights. About methods calculating paleoelevations.
J.A. Raven (2002): Selection pressures on stomatal evolution. PDF file, New Phytologist.
Jennifer Read and Alexia Stokes (2006): Plant biomechanics in an ecological context. PDF file, American Journal of Botany, 93: 1546-1565.
Chantal D. Reid, Robert B. Jackson (Department of Biology, Duke University, Durham, NC), and Joy K. Ward Department of Biology, University of Utah, Salt Lake City, UT: Carbon dioxide as a selective agent for stomatal density. Abstract.
! G.J. Retallack (2001):
300-million-year record of atmospheric carbon dioxide from fossil plant cuticles.
In PDF, Nature. See also:
Supplementary Information for "A 300-million-year record of atmospheric carbon dioxide from fossil plant cuticles" Nature, V411, 287. They are measurements of stomatal index from fossil and living plants. Part 1 has reliable data, and Part 2 has data deemed statistically inadequate from a rarefaction analysis. Abbreviations include SI (stomatal index), Nf (number of fragments counted), Ns (number of stomates counted), Ne (number of epidermal cells counted), and Ma (millions of years ago).
G.J.Retallack, University of Oregon, Eugene: Soils and Global Change in the Carbon Cycle over Geological Time (PDF file).
Markus Riederer, Julius von Sachs Institut, Würzburg: Stoffaustausch über pflanzliche Grenzflächen (in German). Research about plant cuticles.
Sue Rigby, Geology, Geophysics, Environmental Geoscience, Grant Institute, University of Edinburgh: COURSE MATERIALS. Go to: GEP COURSE MATERIALS, Lecture 8: Impacts of life on the planet. PDF file.
Daniel H. Rothman, Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA: Global biodiversity and the ancient carbon cycle. Proc. Natl. Acad. Sci. USA, Vol. 98, Issue 8, 4305-4310, April 10, 2001.
Daniel H. Rothman, Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA: Atmospheric carbon dioxide levels for the last 500 million years. Proc. Natl. Acad. Sci. USA, Vol. 99, Issue 7, 4167-4171, April 2, 2002.
A. Roth-Nebelsick (2007): Computer-based Studies of Diffusion through Stomata of Different Architecture. PDF file, Ann. Bot., 100: 23-32. See also here.
! A. Roth-Nebelsick et al. (2001): Evolution and Function of Leaf Venation Architecture: A Review. PDF file, Annals of Botany 87: 553-566. See also here.
D.L. Royer et al. (2002): High CO2 increases the freezing sensitivity of plants: implications for paleoclimatic reconstructions from fossil floras.. In PDF, Geology, 30: 963-966.
D.L. Royer (2001): Stomatal density and stomatal index as indicators of paleoatmospheric CO2 concentration. PDF file, from Review of Palaeobotany and Palynology 114 (2001) 1-28.
D.L. Royer et al. (2001): ! Phanerozoic atmospheric CO2 change: evaluating geochemical and paleobiological approaches. In PDF, Earth-Science Reviews, 54: 349-392.
D.L. Royer, Department of Geosciences, Pennsylvania State University, University Park, PA: Using stomatal distributions to reconstruct ancient levels of atmospheric CO2
L. Santasalo (2013): The Jurassic extinction events and its relation to CO2 levels in the atmosphere: a case study on Early Jurassic fossil leaves. In PDF, Bachelor´s thesis, Department of Geology, Lund University, Sweden.
ScienceDaily Magazine: Fossil Plants' Ties To Ancient Carbon Redefined.
Laura Serna (2008): Drawing the future: Stomatal response to CO2 levels. PDF file, Plant Signaling and Behavior 3: 214-217. See also here.
Nancy E. Spaulding & Samuel N. Namowitz (McDougal Littell): Exploring Earth. The investigations and visualizations on this site were designed to accompany Earth Science, a high school textbook. The Web site was developed by TERC, a non-profit educational research and development firm in collaboration with McDougal Littell. Funding was provided by the National Science Foundation. Go to: The greenhouse effect and global warming.
! R.A. Spicer (1992):
as Environmental Indicators,
from Plants. PDF file.
Now recovered from the Internet Archive´s Wayback Machine.
M. Steinthorsdottir and V. Vajda (2013): Early Jurassic (late Pliensbachian) CO2 concentrations based on stomatal analysis of fossil conifer leaves from eastern Australia. In PDF, Gondwana Research.
Teaching Issues and Experiments in Ecology (TIEE): TIEE is a project of the Education and Human Resources Committee of the Ecological Society of America. Go to: Environmental Correlates with Leaf Stomata Density. Detailed Description of the Experiment. See also here.
Dieter Uhl and Hans Kerp, Forschungsstelle für Paläobotanik, Westfälische Wilhelms-Universität, Münster: Stomatal-density and -index in Upper Permian conifers. Abstract, The International Plant Taphonomy Meeting 2002, Bonn, Goldfuss Museum, Institute of Paleontology, Germany.
Henk Visscher, Utrecht University: Fossil leaves as biosensors of paleoatmospheric CO2 levels. Abstract (RTF file) of the 2000 lecture series of Petroleum Geologische Kring.
Friederike Wagner, Raimond Below, Pim De Klerk, David L. Dilcher, Hans Joosten, Wolfram M. Kürschner, and Henk Visscher: A natural experiment on plant acclimation: Lifetime stomatal frequency response of an individual tree to annual atmospheric CO2 increase. The National Academy of Sciences, PNAS 1996 93: 11705-11708.
The White Rose Palaeobiology Group. This is a collaborative initiative between the Universities of Sheffield and Leeds. Go to: Atmospheric CO2 - the key to early leaf evolution.
SanPing XIE et al. (2009):
variation in Ginkgo leaf characters: Clues to paleoelevation reconstruction.
PDF file, Science in China Series D: Earth Sciences, 52: 2040-2046.
"The results show that leaf area, petiole length, and stomatal parameters have no obvious linear relationship with altitude (...). The results also suggest that the differences in stomatal density and stomatal index between sun and shade leaves had more influence on paleoelevation reconstruction than that in other parameters".
Carl Zimmer (Carl Zimmer writes the monthly essay in the US magazine Natural History,
having inherited this position from Stephen Jay Gould):
High and dry.
Stomatal apparatus permitting plants to become trees.
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