Home / Ecology & Palaeoenvironment / Plant Roots

Reinhard Agerer, Ludwig-Maximilians-Universität München, and Gerhard Rambold, Universität Bayreuth, Germany: DEEMY. An expert information system with descriptions and images for the characterization and determination of ectomycorrhizae - structures formed by fungi and the roots of forest trees. Go to: Character listing, morphology, mycorrhizal system, morphology mycorrhizal system ramification presence-type.
Now provided by the Internet Archive´s Wayback Machine.

T. Alekseeva et al. (2016): Characteristics of Early Earth's Critical Zone Based on Middle—Late Devonian Paleosol Properties (Voronezh High, Russia). In PDF, Clays and Clay Minerals, 64: 677–694. https://doi.org/10.1346/CCMN.2016.064044.
Note also here.
Note figure 13: Terrane map of western and central Laurussia (including the Laurentian sector) and adjacent areas in the late Devonian (Famennian).

P. Baldrian (2017): Forest microbiome: diversity, complexity and dynamics. Free access, FEMS Microbiology Reviews, 41: 109–130.

M.K. Bamford, University of the Witwatersrand, Johannesburg, South Africa: Methods for reconstructing past vegetation based on macroplant fossils. In PDF.

! H. Beraldi-Campesi (2013): Early life on land and the first terrestrial ecosystems. In PDF, Ecological Processes, 2. See also here.
Note figure 1: Suggested chronology of geological, atmospheric, and biological events during the Hadean, Archean, and Paleoproterozoic eons.

C.M. Berry and J.E.A. Marshall (2015): Lycopsid forests in the early Late Devonian paleoequatorial zone of Svalbard. Free access, Geology, 43: 1043-1046.

Margaret E. Berry and James R. Staub, Department of Geology, Southern Illinois University, Carbondale, IL: Root Traces and the Identification of Paleosols.

! M. Bertling et al. (2022): Names for trace fossils 2.0: theory and practice in ichnotaxonomy. Free access, Lethaia, 55.
Note figure 2: Preservation types of plant roots.

P. Bonfante and A. Genre (2010): Mechanisms underlying beneficial plant - fungus interactions in mycorrhizal symbiosis. PDF file, Nature Communications.

V. Borruel-Abadía et al. (2015): Climate changes during the Early–Middle Triassic transition in the E. Iberian plate and their palaeogeographic significance in the western Tethys continental domain. In PDF, Palaeogeography, Palaeoclimatology, Palaeoecology, 440: 671–689.
See also here.

! M.C. Brundrett (2002): Coevolution of roots and mycorrhizas of land plants. In PDF, New phytologist, 154: 275-304.
This expired link is available through the Internet Archive´s Wayback Machine.

Mark Brundrett , CSIRO Forestry and Forest Products:
The Mycorrhiza Site. Introduction to mycorrhizal associations, structure and development or roots and mycorrhizas. Chiefly information about Australian plants and fungi. See also:
The older webpage.
Books and cited references.
and Text books on mycorrhizas.
These expired links are available through the Internet Archive´s Wayback Machine.

Mark Brundrett , CSIRO Forestry and Forest Products: Roots. An introduction to the root structures which influence mycorrhizal fungi. Including root systems and root growth.
This expired link is available through the Internet Archive´s Wayback Machine.

R. Buckley Trabuco Canyon, California: Inducing adventitious root growth in cycad leaves. Reprinted with permission from The Cycad Newsletter, Issue 1, 1999.
Still available through the Internet Archive´s Wayback Machine.

Frances M. Cardillo, Manhattan College: Plant System Tissues. Snapshot taken by the Internet Archive´s Wayback Machine. Go to: Tissue Systems of the Root.

S.N. Césari et al. (2021): Nurse logs: An ecological strategy in a late Paleozoic forest from the southern Andean region. In PDF, Geology, 38: 295-298.
See also here.
"... Decaying logs on the forest floor can act as “nurse logs” for new seedlings, helping with the regeneration of the vegetation.
[...] Little rootlets preserved inside the wood of several specimens indicate that seedlings developed on these logs. ..."

B.-Y. Chen et al. (2022): Anatomy of Stigmaria asiatica Jongmans et Gothan from the Asselian (lowermost Permian) of Wuda Coalfield, Inner Mongolia, North China. In PDF, Palaeoworld, 31: 311–323.
See also here.

Citable reviews in the life sciences (Wiley). Go to:
Soil.

! Michael Clayton, Department of Botany, University of Wisconsin, Madison: Instructional Technology (BotIT). Some image collections. Excellent! Go to:
Root

Michael Clayton, Department of Botany, University of Wisconsin, Madison: The Virtual Foliage. Go to: Root Images.

! Harold G. Coffin, Geoscience Research Institute, Loma Linda, CA: THE YELLOWSTONE PETRIFIED "FORESTS". All about the petrified forests of Yellowstone National Park in Wyoming and Montana.
Website outdated, download a version archived by the Internet Archive´s Wayback Machine.

! C.E. Colombi and J.T. Parrish (2008): Late Triassic Environmental Evolution in Southwestern Pangea: Plant Taphonomy of the Ischigualasto Formation. In PDF, Palaios, 23: 778–795.
Still available via Internet Archive Wayback Machine.
See also here.

D. Corenblit et al. (2015): Considering river structure and stability in the light of evolution: feedbacks between riparian vegetation and hydrogeomorphology. In PDF, Earth Surface Processes and Landforms, 40. See also here.

John D. Curtis, Biology Department, University of Wisconsin; Nels R. Lersten, Department of Botany, Iowa State University, and Michael D. Nowak, Biology Department, University of Wisconsin: Photographic Atlas of Plant Anatomy. Go to: Root Systems.

M.P. D'Antonio and F. Herrera (2024): New Evidence of Unequal Branching in Stigmaria ficoides (Lycopsida). Open access, International Journal of Plant Sciences, 185.
"... Stigmaria ficoides is the main form species of rooting organ for late Paleozoic arborescent lycopsids in the families Diaphorodendraceae and Lepidodendraceae.
[...] we report two S. ficoides specimens based on the presence of the diagnostic rootlet scar pattern ..."

N.S. Davies et al.(2024): Earth's earliest forest: fossilized trees and vegetation-induced sedimentary structures from the Middle Devonian (Eifelian) Hangman Sandstone Formation, Somerset and Devon, SW England. Open access, Journal of the Geological Society. https://doi.org/10.1144/jgs2023-204.

A.-L. Decombeix et al. (2011): Root suckering in a Triassic conifer from Antarctica: Paleoecological and evolutionary implications. In PDF, American Journal of Botany, 98: 1222-1225.

C. de Vega et al. (2011): Mycorrhizal fungi and parasitic plants: Reply. Free access, American Journal of Botany, 98: 597-601.

W.A. DiMichele et al. (2022): Stigmaria: A Review of the Anatomy, Development, and Functional Morphology of the Rootstock of the Arboreous Lycopsids. Abstract, International Journal of Plant Sciences.
"... We reevaluate the conventional view that the rootlets were abscised, ..."
"... In soil, rootlets improved anchorage, whereas in open water, largely hollow mature roots may have enhanced stigmarian system buoyancy and nucleated floating peat mats. ..."

William A. DiMichele et al. (2010): Cyclic changes in Pennsylvanian paleoclimate and effects on floristic dynamics in tropical Pangaea. PDF file, International Journal of Coal Geology, 83: 329-344. See also here.

R.F. Dubiel (1992): Sedimentology and Depositional History of the Upper Triassic Chinle Formation in the Uinta, Piceance, and Eagle Basins, Northwestern Colorado and Northeastern Utah. In PDF, See also here (Google books).

! J. Enga (2015): Paleosols in the Triassic De Geerdalen and Snadd formations. In PDF, Master thesis, Norges teknisk-naturvitenskapelige universitet. See also here.

F.A.A. Feijen et al. (2018): Evolutionary dynamics of mycorrhizal symbiosis in land plant diversification. In PDF, Scientific reports.

Z. Feng et al. (2022): Nurse logs: A common seedling strategy in the Permian Cathaysian Flora. In PDF, iScience, 25.
See also here.
"... We report seven coniferous nurse logs from lowermost to uppermost Permian strata of northern China that have been colonized by conifer and sphenophyllalean roots. These roots are associated with two types of arthropod coprolites and fungal remains. ..."

K.J. Field et al. (2015): Symbiotic options for the conquest of land. In PDF, Trends in Ecology and Evolution, 30: 477-486. See also here.

S.J. Fischer and S.T. Hasiotis (2018): Ichnofossil assemblages and palaeosols of the Upper Triassic Chinle Formation, south-eastern Utah (USA): Implications for depositional controls and palaeoclimate. Annales Societatis Geologorum Poloniae, 88: 127-162. See also here.

J.E. Francis, Earth Sciences, University of Leeds: Fossil Trees in the Basal Purbeck Formation on Portland - The Great Dirt Bed Forest.
The link is to a version archived by the Internet Archive´s Wayback Machine.

R.A. Gastaldo (1992): Regenerative growth in fossil horsetails following burial by alluvium. In PDF, Historical Biology: An International Journal of Paleobiology, 6: 203-219. See also here
and there.

C.T. Gee et al. (2018): Fossil burrow assemblage, not mangrove roots: reinterpretation of the main whale-bearing layer in the late Eocene of Wadi Al-Hitan, Egypt. Abstract, Palaeobiodiversity and Palaeoenvironments, 99: 143–158. See also here (in PDF).

N. Geldner and D.E. Salt (2014): Focus on Roots. Free access, Plant Physiology, 166: 453–454.

! A. Genre et al. (2020): Unique and common traits in mycorrhizal symbioses. In PDF, Nature Reviews Microbiology, 18, 649–660.
See also here.
Note figure 1: Major mycorrhizal types.
"... Mycorrhizas are among the most important biological interkingdom interactions, as they involve ~340,000 land plants and ~50,000 taxa of soil fungi
[...] During evolution, mycorrhizal fungi have refined their biotrophic capabilities to take advantage of their hosts as food sources and protective niches, while plants have developed multiple strategies to accommodate diverse fungal symbionts ..."

Pamela J.W. Gore, Department of Geology, Georgia Perimeter College, Clarkston, GA: Historical Geology. Online laboratory manual. Snapshot taken by the Internet Archive´s Wayback Machine. Go to: Fossil Preservation Laboratory.

David R. Greenwood, Zoology Dept., Brandon University, Manitoba, Canada: Mummified tree stumps on Axel Heiberg Island, Canada (PDF file). In low grade lignite preserved tree stumps.
The link is to a version archived by the Internet Archive´s Wayback Machine.

L. Guo et al. (2024): Evolutionary and ecological forces shape nutrient strategies of mycorrhizal woody plants. Free access, Ecology Letters, 27.
See likewise here.
Note figure 1: Phylogenetic tree of the species that have data related to nutrient acquisition strategies.

H. Hagdorn et al. (2015): 15. Fossile Lebensgemeinschaften im Lettenkeuper. - p. 359-385, PDF file, in German. Go to PDF page 3:
! Equisetites roots from the germanotype Lower Keuper (Lettenkeuper, Erfurt Formation, Ladinian, Triassic).
In: Hagdorn, H., Schoch, R. & Schweigert, G. (eds.): Der Lettenkeuper - Ein Fenster in die Zeit vor den Dinosauriern. Palaeodiversity, Special Issue (Staatliches Museum für Naturkunde Stuttgart).
! You may also navigate via back issues of Palaeodiversity 2015. Then scroll down to: Table of Contents "Special Issue: Der Lettenkeuper - Ein Fenster in die Zeit vor den Dinosauriern".
Still available via Internet Archive Wayback Machine.

H. Hagdorn et al. (2015): 15. Fossile Lebensgemeinschaften im Lettenkeuper. - p. 359-385, PDF file, in German. Go to PDF page 3:
! Equisetites roots from the germanotype Lower Keuper (Lettenkeuper, Erfurt Formation, Ladinian, Triassic).
In: Hagdorn, H., Schoch, R. & Schweigert, G. (eds.): Der Lettenkeuper - Ein Fenster in die Zeit vor den Dinosauriern. Palaeodiversity, Special Issue (Staatliches Museum für Naturkunde Stuttgart).
! Navigate from here for other downloads (back issues of Palaeodiversity 2015, scroll down to "Special Issue: Der Lettenkeuper ...").

A.J. Hetherington (2024): The role of fossils for reconstructing the evolution of plant development. Free access, The Company of Biologists, 151.
Note figure 1: Fossils indicate that roots and leaves evolved independently in vascular plants.
"... The focus of this Spotlight is to showcase the rich plant fossil record open for developmental interpretation and to cement the role that fossils play at a time when increases in genome sequencing and new model species make tackling major questions in the area of plant evolution and development tractable for the first time ..."

! A.J. Hetherington (2024): Fossil evidence supports at least two origins of plant roots. PDF file, pp. 3-18, in: T. Beeckman & A. Eshel (eds.), Plant Roots: The Hidden Half. Fifth edn, CRC Press, Boca Raton.
See likewise here.
Note figure 1.4: Geological timeline showing major events in early land plant evolution.
! Figure 1.8, A: Complex rooting system of Asteroxylon mackiei composed of root-bearing axes and rooting axes. A, Artists reconstruction of A. mackiei in life.

A.J. Hetherington et al. (2021): An evidence-based 3D reconstruction of Asteroxylon mackiei the most complex plant preserved from the Rhynie chert. Free access, eLife. See also here, and there. Worth checking out:
Zu den Wurzeln der pflanzlichen Evolution (ORF.at, in German).
Forscher rekonstruieren, wie die ersten Wurzeln Fuß fassten (Der Standard, in German).

A.J. Hetherington et al. (2020): Multiple origins of dichotomous and lateral branching during root evolution. Abstracts, Nature Plants, 6: 454–459. See also here (in PDF).

A.J. Hetherington and L. Dolan (2019): Rhynie chert fossils demonstrate the independent origin and gradual evolution of lycophyte roots. Abstract, Current opinion in plant biology, 47: 119-126. See also here and there (in PDF).

! A.J. Hetherington and L. Dolan (2018): Stepwise and independent origins of roots among land plants. Free access, Nature, 561: 235–238. Author manuscript; available in PMC 2019.

! A.J. Hetherington et al. (2016). Networks of highly branched stigmarian rootlets developed on the first giant trees. Free access, Proceedings of the National Academy of Sciences, USA, 113: 6695–6700.

A. Hetherington (2017): Evolution and morphology of lycophyte root systems. In PDF, Thesis, St Catherine’s College, Department of Plant Sciences, University of Oxford. See also here.

! A.J. Hetherington et al. (2016): Unique Cellular Organization in the Oldest Root Meristem. In PDF, Current Biology.
See also here and there (Botany One).

! A.J. Hetherington and L. Dolan (2016): The evolution of lycopsid rooting structures: conservatism and disparity. In PDF, New Phytologist.

! A.J. J. Hetherington et al. (2016): Networks of highly branched stigmarian rootlets developed on the first giant trees. In PDF, PNAS, 113.

! A Ielpi et al. (2015): Impact of Vegetation On Early Pennsylvanian Fluvial Channels: Insight From the Joggins Formation of Atlantic Canada. In PDF, Journal of Sedimentary Research, 85: 999-1018.

P. Kenrick and C. Strullu-Derrien (2014): The Origin and Early Evolution of Roots. In PDF, Plant Physiology, 166: 570-580. See also here (abstract).

H. Khalilizadeh et al. (2022): Two fossilized swamps containing in situ Sphenophyta stems, rhizomes, and root systems from the Middle Jurassic Hojedk Formation, Kerman area (Iran) . In PDF, Palaeobiodiversity and Palaeoenvironments.
See also here.

Khudadad (2021): A Middle Devonian vernal pool ecosystem provides a snapshot of the earliest forests. Open access, PLoS ONE 16(9): e0255565.

A.A. Klymiuk and B.A. Sikes (2019): Suppression of root-endogenous fungi in persistently inundated Typha roots. Free access, Mycologia. See also:
ScienceDaily (2019): Fungi living in cattail roots could improve our picture of ancient ecoystems.

Ross Koning, Biology Department, Eastern Connecticut State University, Willimantic, CT: Biology of Plants. Snapshot taken by the Internet Archive´s Wayback Machine. Go to:
! Root Vocabulary.
Roots.

D. Knaust (2015): Trace fossils from the continental Upper Triassic Kågeröd Formation of Bornholm, Denmark. In PDF, Annales Societatis Geologorum Poloniae, 85: 481–492.
Please take notice: Fig. 7, root traces (rhizoliths) in fine- to medium-grained sandstone.

J. Kowal et al. (2018): From rhizoids to roots? Experimental evidence of mutualism between liverworts and ascomycete fungi. In PDF, Annals Of Botany, 121: 221-227. See also here.

! M.J. Kraus and S.T. Hasiotis (2006): Significance of different modes of rhizolith preservation to interpreting paleoenvironmental and paleohydrologic settings: examples from Paleogene paleosols. In PDF, Journal of Sedimentary Research, 76: 633-646.
The link is to a version archived by the Internet Archive´s Wayback Machine.

Khudadad (2021): A Middle Devonian vernal pool ecosystem provides a snapshot of the earliest forests. Open access, PLoS ONE 16(9): e0255565.
Note figure 14: Representative fossils of roots systems belonging to three Middle Devonian tree clades.

A. Lakehal et al. (2023): Specification and evolution of lateral roots. In PDF, Current Biology.
See also here.
"... we point out that positional control of lateral root stem cell specification has not been the prevailing mechanism among all plants and discuss the process in ferns ..."
Note figure 1: Evolution of root branching in land plants.

! M.A.K. Lalica and A.M.F. Tomescu (2021): The early fossil record of glomeromycete fungi: New data on spores associated with early tracheophytes in the Lower Devonian (Emsian; c. 400 Ma) of Gaspé (Quebec, Canada). In PDF, Review of Palaeobotany and Palynology. See also here.
"... occurrence in fluvial-coastal environments and their putative mycorrhizal role suggest that glomeromycetes were relatively ubiquitous symbionts of tracheophytes, ..."

M. Lu et al. (2019): Geochemical Evidence of First Forestation in the Southernmost Euramerica from Upper Devonian (Famennian) Black Shales. Free access, Scientific Reports, 9.
"... Plant residues (microfossils, vitrinite and inertinite) and biomarkers derived from terrestrial plants and wildfire occur throughout the stratigraphic section, suggesting widespread forest in the southern Appalachian Basin, a region with no macro plant fossil record during the Famennian. Inorganic geochemical results, as shown by increasing values of SiO2/ Al2O3, Ti/Al, Zr/Al, and the Chemical Index of Alteration (CIA) upon time sequence, suggest enhanced continental weathering that may be attributed to the invasion of barren lands by rooted land plants. ..."

L. Luthardt et al. (2016): Palaeoclimatic and site-specific conditions in the early Permian fossil forest of Chemnitz—Sedimentological, geochemical and palaeobotanical evidence. In PDF, Palaeogeography, Palaeoclimatology, Palaeoecology, 441: 627–652.
See also here.

! D.W. Malloch et al. (1980): Ecological and evolutionary significance of mycorrhizal symbioses in vascular plants (a review). In PDF, PNAS, 77.

L. Luthardt et al. (2016): Palaeoclimatic and site-specific conditions in the early Permian fossil forest of Chemnitz—Sedimentological, geochemical and palaeobotanical evidence. Abstract, Palaeogeography, Palaeoclimatology, Palaeoecology, 441: 627–652. See also here.

Anthony J. Martin, Geosciences Program, Emory University, Atlanta, GA: Trace Fossil Images Page, Plant Trace Fossils. Modern and fossil root traces.
This expired link is available through the Internet Archive´s Wayback Machine.

! F. Martin et al. (2016): Unearthing the roots of ectomycorrhizal symbioses. Abstract, Nature Reviews Microbiology, 14: 760–773. See also here (in PDF).

! K.K.S. Matsunaga and A.M.F. Tomescu (2016): Root evolution at the base of the lycophyte clade: insights from an Early Devonian lycophyte. Free access, Annals of botany, 117: 585–598.

! B. Meyer-Berthaud et al. (2013): Archaeopterid root anatomy and architecture: new information from permineralized specimens of Famennian age from Anti-Atlas (Morocco). In PDF, Int. J. Plant Sci., 174: 364–381.

B. Meyer-Berthaud and A.L. Decombeix (2012): Palaeobotany: in the shade of the oldest forest. In PDF, Nature 483: 41-42.

! B.J.W. Mills et al. (2017): Nutrient acquisition by symbiotic fungi governs Palaeozoic climate transition. Open access, Phil. Trans. R. Soc. B, 373.

R.L. Mitchell et al. (2023): Terrestrial surface stabilisation by modern analogues of the earliest land plants: A multi-dimensional imaging study. Open access, Geobiology.
Note figure 1: Summary chart highlighting the evolution of different CGC elements [cryptogamic ground covers] from contrasting molecular, phylogenetic and fossil dating methods, and schematic land plant phylogeny of modern terrestrial organisms, focussing on the bryophytes and specific liverwort genera.

R.L. Mitchell et al. (2021): Cryptogamic ground covers as analogues for early terrestrial biospheres: Initiation and evolution of biologically mediated proto-soils. Open access, Geobiology, 19: 292-306.
Note fig. 8: Illustrations summarising the key features in modern lichen, thalloid plant, moss and mixed proto-soils.

! J.L. Morris et al. (2015): Investigating Devonian trees as geo-engineers of past climates: linking palaeosols to palaeobotany and experimental geobiology. In PDF, Palaeontology, 58: 787-801. See also here.

T.E. Mottin et al. (2022): A glimpse of a Gondwanan postglacial fossil forest. In PDF, Palaeogeography, Palaeoclimatology, Palaeoecology, 588. See also here.

S. Oplustil et al. (2014): T⁰ peat-forming plant assemblage preserved in growth position by volcanic ash-fall: A case study from the Middle Pennsylvanian of the Czech Republic. In PDF, Bulletin of Geosciences, 89: 773–818.

! T.J. Orr and E.M. Roberts (2024): A review and field guide for the standardized description and sampling of paleosols. Open access, Earth-Science Reviews, 253.
"... Paleosols are unrivaled terrestrial archives of paleoclimatic, paleoecological, and paleoenvironmental conditions
[...] we have illustrated and tabulated key paleosol features and classification schemes, including horizon determination and classification; ped determination and classification; mottle description; mineral accumulation description/morphology; burrow/chamber morphology and description; and rhizolith morphology and classification ..."

D. Ortlam (1980): Erkennung und Bedeutung fossiler Bodenkomplexe in Locker- und Festgesteinen. PDF file, in German. Geol. Rdschau, 69: 581-593.

D. Ortlam (1974): Inhalt und Bedeutung fossiler Bodenkomplexe in Perm und Trias von Mitteleuropa. PDF file, in German. Geol. Rdschau, 63: 850-884.

! J.G. Pausas et al. (2018): Unearthing belowground bud banks in fire-prone ecosystems. Free access, New Phytologist, 217: 1387-1778.
Note figure 1: Stylized diagrams of 16 belowground bud bank (BBB) structures that enable plants to resprout following fire.
Figure 3: Oldest time of origin for different belowground bud bank (BBB) organs in selected angiosperm families.
"... Recognizing the diversity of BBBs provides a basis for understanding the many evolutionary pathways available to plants for responding to severe recurrent disturbances. ..."

£. Pawlik et al. 2020): Impact of trees and forests on the Devonian landscape and weathering processes with implications to the global Earth's system properties – A critical review. In PDF, Earth-Science Reviews, 205: doi 10.1016/j.earscirev.2020.103200.
See also here.
Note fig. 2. Spatial configuration of continents in the Devonian.
Note fig. 3: Landscape reconstruction with stands of Pseudosporochnus, up to 4 m high, with Protopteridium in shruby layer and herbaceous Drepanophycus and Protolepidodendron in understorey.
Note fig. 6: A close look at trees diversification and selected accompanying events in the Devonian.

! T.O. Perry (1989): Tree roots: facts and fallacies. In PDF, Arnoldia, 49: 3-21.

M.P. Pound et al. (2017): Deep Machine Learning provides state-of-the-art performance in image-based plant phenotyping. GigaScience. See also here (in PDF).

C. Puginier et al. (2021): Plant–microbe interactions that have impacted plant terrestrializations. Free access, Plant Physiology.
Note figure 1: 1 Phylogenetic tree of the Viridiplantae. showing the evolution of the AMS [arbuscular mycorrhizal symbiosis], the putative evolutions of lichens and clades that contain LFA [lichen forming algae] and terrestrial species.
Figure 3: Lichens and their tolerance against terrestrial-related constraints.

! M. Qin et al. (2024): In situ forest with lycopsid trees bearing lobed rhizomorphs from the Upper Devonian of Lincheng, China. Free access, PNAS Nexus, 3. pgae241, https://doi.org/10.1093/pnasnexus/pgae241.
Note figure 7: Reconstruction of Heliodendron’s rooting system.
"... The Devonian witnessed the transformation from clastic nonlycopsid dominated forests to Carboniferous swampy forests dominated by giant lycopsid trees. These trees form a multigenerational community, as shown by the in situ preserved stems at various levels ..."

J.A. Raven and D. Edwards (2001): Roots: evolutionary origins and biogeochemical significance. PDF file, J. Exp. Bot., 52: 381-401.

! B. Reinhold-Hurek et al. (2015): Roots Shaping Their Microbiome: Global Hotspots for Microbial Activity. Free access, The Annual Review of Phytopathology, 53: 403–423.

! R. Rellán-Álvarez et al. (2016): Environmental control of root system biology. In PDF, Annual Reviews Plant Biology, 67: 1–26.

! W. Remy et al. (1994): Four hundred-million-year-old vesicular arbuscular mycorrhizae. In PDF, PNAS. See also here.

! G.J. Retallack (1985): Fossil soils as grounds for interpreting the advent of large plants and animals on land. In PDF, Philosophical Transactions of the Royal Society, London B, 309: 105-142.

L.F. Rinehart et al. (2015): Plant architecture and spatial structure of an early Permian woodland buried by flood waters, Sangre de Cristo Formation, New Mexico. In PDF, Palaeogeography, Palaeoclimatology, Palaeoecology.

D. Rockenbach Boardman et al. (2016): A new genus of Sphenopsida from the Lower Permian of the Paraná Basin, Southern Brazil. In PDF, Review of Palaeobotany and Palynology, 233: 44–55. See also here and there.

R. Rößler (2014): Die Bewurzelung permischer Calamiten: Aussage eines Schlüsselfundes zur Existenz freistehender baumförmiger Schachtelhalmgewächse innerhalb der Paläofloren des äquatornahen Gondwana. PDF file, in German. The roots of Permian calamitaleans - a key find suggests the existence of free-stemmed arborescent sphenopsids among the low latitude palaeofloras of Gondwana. Freiberger Forschungshefte, C 548.

R. Rößler et al. (2014): The root systems of Permian arborescent sphenopsids: evidence from the Northern and Southern hemispheres. In PDF, see also here (abstract).

! R. Rößler et al. (2012): The largest calamite and its growth architecture - Arthropitys bistriata from the Early Permian Petrified Forest of Chemnitz. In PDF, Review of Palaeobotany and Palynology, 185: 64-78.
The link is to a version archived by the Internet Archive´s Wayback Machine.

S. Saha et al. (2023): Fine root decomposition in forest ecosystems: an ecological perspective. Free access, Front. Plant Sci., 14. doi: 10.3389/fpls.2023.1277510.

H. Sato (2023): The evolution of ectomycorrhizal symbiosis in the Late Cretaceous is a key driver of explosive diversification in Agaricomycetes. Free access, New Phytologist, 241: 444-460.
Note figure 7: Historical character transition of ectomycorrhizal (EcM) symbiosis and dynamics of net diversification rates.
"... Ectomycorrhizal (EcM) symbiosis, a ubiquitous plant–fungus interaction in forests, evolved in parallel in fungi
[...] findings suggest that the evolution of EcM symbiosis in the Late Cretaceous, supposedly with coevolving EcM angiosperms, was the key drive of the explosive diversification in Agaricomycetes ..."

E. Schuettpelz and S.B. Hoot (2006): Inferring the Root of Isoetes: Exploring Alternatives in the Absence of an Acceptable Outgroup. Abstract, Systematic Botany, 31: 258-270.

A.B. Schwendemann et al. (2011): Morphological and functional stasis in mycorrhizal root nodules as exhibited by a Triassic conifer. In PDF.

! M.-A. Selosse and F. Rousset (2011): The Plant-Fungal Marketplace. In PDF, Science.

S.S.T. Simon et al. (2018): An exhumed fine-grained meandering channel in the lower Permian Clear Fork Formation, north-central Texas: Processes of mud accumulation and the role of vegetation in channel dynamics. In PDF, Int. Assoc. Sedimentol., Spec. Publ., 48: 149–172.
See also here.
"... weakly laminated mudstone with desiccation cracks contains leaves and seeds of Evolsonia texana, marattialean foliage and Taeniopteris sp., with root traces penetrating the leaves. ..."

! M.S. Smart et al. (2022): Enhanced terrestrial nutrient release during the Devonian emergence and expansion of forests: Evidence from lacustrine phosphorus and geochemical records. Free access, GSA Bulletin. Note also:
Können Wurzeln töten? By P. Heinemann, Frankfurter Allgemeine, March 07, 2023 (in German).

! F. Sønderholm and C.J. Bjerrum (2021): Minimum levels of atmospheric oxygen from fossil tree roots imply new plant-oxygen feedback. Open access, Geobiology,19: 250–260.
"... we consider archaeopterid fossil root systems, resembling those of modern mature conifers.
...The absence of large and deeply penetrating roots prior to the Middle Devonian may have been related to low atmospheric O₂ pressures, but it is just as likely that the early evolution of roots reflects structural plant evolution rather than available soil O₂. ..."

V. Spencer et al. (2020): What can lycophytes teach us about plant evolution and development? Modern perspectives on an ancient lineage. Open access, Evolution & Development, 23: 174–196.

! R.A. Spicer (1989): Physiological characteristics of land plants in relation to environment through time. In PDF, Earth and Environmental Science Transactions of The Royal Society of Edinburgh, 80.
See also here.

! W.E. Stein et al. (2019): Mid-Devonian Archaeopteris Roots Signal Revolutionary Change in Earliest Fossil Forests. Free access, Current Biology, https://doi.org/10.1016/j.cub.2019.11.067. See also here (in PDF).
Worth checking out:
Scientists have discovered the world’s oldest forest—and its radical impact on life (by Colin Barras, Science Magazine, www.sciencemag.org/news/).

W.E. Stein et al. (2012): Surprisingly complex community discovered in the mid-Devonian fossil forest at Gilboa. Abstract, Nature, 483. Numerous Eospermatopteris root systems in life position within a mixed-age stand of trees, large woody rhizomes with adventitious roots.

! C. Strullu-Derrien et al. (2018): The origin and evolution of mycorrhizal symbioses: from palaeomycology to phylogenomics. Free access, New Phytologist, 220: 1012–1030.
! Note figure 1: Geological timescale with oldest known fossils. Left: Antiquity of genomic traits related to mycorrhizal evolution based on molecular clock estimates. Right: Oldest known fossils.
Figure 5: Simplified phylogenetic tree showing the minimum stratigraphic ranges of selected groups based on fossils (thick bars) and their minimum implied range extensions (thin lines).

! C. Strullu-Derrien et al. (2016): Origins of the mycorrhizal symbioses. PDF file, In: F Martin (ed.): Molecular Mycorrhizal Symbiosis, John Wiley & Sons.

N.J. Tabor et al. (2013): Conservatism of Late Pennsylvanian vegetational patterns during short-term cyclic and long-term directional environmental change, western equatorial Pangea. Geol Soc Spec Publ., 376: 201–234; available in PMC 2014.

L.H. Tanner et al. (2014): Pedogenic and lacustrine features of the Brushy Basin Member of the Upper Jurassic Morrison Formation in Western Colorado: Reassessing the paleoclimate interpretations. In PDF.

L.H. Tanner and S.G. Lucas (2007): Origin of sandstone casts in the Upper Triassic Zuni Mountains Formation, Chinle Group, Fort Wingate, New Mexico. In PDF, New Mexico Museum of Natural History and Science Bulletin, 40: 209–214.
Now recovered from the Internet Archive´s Wayback Machine.
See also here (provided by Google books).
"... We propose alternatively that the casts are rhizoliths formed by the deep tap roots of the sphenopsid Neocalamites. ..."

! B.A. Thomas and L.J. Seyfullah (2015): Stigmaria Brongniart: a new specimen from Duckmantian (Lower Pennsylvanian) Brymbo (Wrexham, North Wales) together with a review of known casts and how they were preserved. Abstract, Geological Magazine, 152: 858–870. See also here (in PDF).

! A.M.F. Tomescu et al. (2016): Microbes and the fossil record: selected topics in paleomicrobiology. Abstract, in: Hurst C. (ed.) Their World: A Diversity of Microbial Environments. Advances in Environmental Microbiology, vol 1: 69-169. See also here (in PDF).

A.M.F. Tomescu (2016): Development: Paleobotany at the High Table of Evo-Devo. Free access, Current Biology, 26: R505-R508.

A.M. Trendell et al. (2013): Determining Floodplain plant distributions and populations using paleopedology and fossil root traces: Upper Triassic Sonsela Member of the Chinle Formation at Petrified Forest National Park, Arizona. Abstract, Palaios.

! M.G.A. van der Heijden et al. (2015): Mycorrhizal ecology and evolution: the past, the present, and the future. In PDF, New Phytologist, 205: 1406–1423. See also here.

L.G. van Galen et al. (2023): Correlated evolution in an ectomycorrhizal host–symbiont system. Open access, New Phytologist, 238: 1215–1229doi: 10.1111/nph.18802.

! M. Van Noordwijk et al. (2015): Root distribution of trees and crops: competition and/or complementarity. In PDF, In: Ong, Chin K.; Black, Colin R.; Wilson, Julia, (eds.): Tree-crop interactions: agroforestry in a changing climate. 2nd ed. Wallingford, UK, CAB International, 221-257.

! A.J. van Loon (2009): Soft-sediment deformation structures in siliciclastic sediments: an overview. I)n PDF, Geologos, 15: 3–55.
See also here.
"... various deformational processes, which are subdivided here into (1) endogenic processes resulting in endoturbations; (2) gravity-dominated processes resulting in graviturbations, which can be subdivided further into (2a) astroturbations, (2b) praecipiturbations, (2c) instabiloturbations, (2d) compagoturbations and (2e) inclinaturbations; and (3) exogenic processes resulting in exoturbations, which can be further subdivided into (3a) bioturbations – with subcategories (3a’) phytoturbations, (3a’’) zooturbations and (3a’’’) anthropoturbations – (3b) glaciturbations, (3c) thermoturbations, (3d) hydroturbations, (3e) chemoturbations, and (3f) eoloturbations. ..."

Y.P. Veenma et al. (2023): Biogeomorphology of Ireland's oldest fossil forest: Plant-sediment and plant-animal interactions recorded in the Late Devonian Harrylock Formation, Co. Wexford. Free access, Palaeogeography, Palaeoclimatology, Palaeoecology, 621.
Note figure 6, 7: Lignophyte root systems within the lower Sandeel Bay plant bed.
"... new evidence for early plant-sediment interactions from the Late Devonian (Famennian) Harrylock Formation (County Wexford, Ireland), which hosts standing trees that represent Ireland's earliest known fossil forest.
[...] Fossilized driftwood preserved in the lacustrine facies contains the earliest evidence for arthropod(?) borings in large vascular plant debris. Together these early examples show that plant-sediment and plant-animal interactions, frequently recorded in Carboniferous strata, were already in existence by the Devonian ..."

! B. Wang and Y.-L. Qiu (2006): Phylogenetic distribution and evolution of mycorrhizas in land plants. In PDF, Mycorrhiza, 16: 299-363. See also here.

! D. Wang et al. (2019): The Most Extensive Devonian Fossil Forest with Small Lycopsid Trees Bearing the Earliest Stigmarian Roots. Current Biology, 29: 2604-2615. See also here (in PDF).
Note figure 6: Reconstruction of Guangdedendron.
! Note figure 7: Reconstruction of Xinhang Forest Landscape.
Also worth checking out: Ältester fossiler Wald Asiens entdeckt. Scinexx, in German.

Wayne´s Word.
Biology and Botany, Stem and Root Anatomy. Cellular structure of vascular plants.
The link is to a version archived by the Internet Archive´s Wayback Machine.

David T. Webb, University of Hawaii at Manoa, Honolulu: Plant Anatomy Home Page. Lecture notes. Snapshot taken by the Internet Archive´s Wayback Machine. Go to:
Roots.

M. Wei-Haas (2019): Bizarre Fossils Reveal Asia's Oldest Known Forest. National Geographic Australia.

! Ian West, Southampton University: The Fossil Forest - East of Lulworth Cove, Dorset.

www.kieseltorf.de. Permineralized plant fossils from Germany (in German).

! J. Xue et al. (2016): Belowground rhizomes in paleosols: The hidden half of an Early Devonian vascular plant. In PDF, Proceedings of the National Academy of Sciences of the United States of America, 113. See also here (abstract).

X. Yang et al. (2023): Spatial transcriptomics of a lycophyte root sheds light on root evolution. Abstract, Current Biology, 33.

! R.W. Zobel and Y. Waisel (2010): A plant root system architectural taxonomy: A framework for root nomenclature. In PDF, Plant Biosystems, 144: 507-512. See also here.