La inspiración existe, pero tiene que encontrarte trabajando.

Pablo Picasso

Our group includes undergraduate and graduate students who seek a deeper understanding of plant biology and work to develop expertise in scientific research and the dissemination of its results. We study the plant fossil record and developmental anatomy to understand the evolution of plant form, patterns of plant diversity through time and plant phylogeny.


Research Directions

We study the plant fossil record and developmental anatomy to understand the evolution of plant form, patterns of plant diversity through time and plant phylogeny.

Fossil studies investigate the Late Ordovician – Silurian terrestrial biotas and land plant evolution, Early Devonian floras and their bearing on bryophyte and vascular plant evolution, and plant diversity in the floras of the Early Permian and Early Cretaceous.

Studies of extant plants address the evolution of vascular architecture, roots, and the layers marking the boundary between vascular and ground tissues.

Early Devonian Floras

As the first stage of the ‘Devonian Explosion’, the Early Devonian witnessed the early phases in the evolutionary radiation of vascular plants. Because of that, Early Devonian floras are key to understanding the origins and phylogeny of major tracheophyte lineages and, more generally, deep plant phylogeny.

Research focuses on two North American floras:

  1. The Beartooth Butte Formation of Wyoming hosts the only extensive Early Devonian flora known in western North America, which includes zosterophylls, early lycopsids and trimerophytes of Lochkovian – Emsian age (415-395 Ma) preserved as compressions; bryophyte- and protracheophyte-grade plants are also present, along with algae and animals (microconchids, eurypterids and fish). Work in the Beartooth Butte Formation is aimed at a monographic treatment of the flora (taxonomy, systematics) and understanding of the sedimentology and depositional environments of the fossiliferous layers. The abundant lycophyte material is studied for whole-plant reconstructions, whereas in situ preserved plants provide insights into the three-dimensional architecture of the earliest rooting systems. Field trips for fossil collecting are organized about every other year.

  2. The Battery Point Formation and coeval units in the Gaspe Peninsula of Quebec and in New Brunswick host an Emsian (407-395 Ma) flora representing one of the rare occurrences of anatomically preserved plants in the Early Devonian. We study Gaspe specimens on loan from the National Museum of Natural History – Smithsonian Institution, to characterize the sporangia and spores of the best known trimerophyte, Psilophyton, as well as to document plant diversity in the flora (including some of the oldest occurrences of secondary growth/wood production) and to provide whole-plant reconstructions.

Cryptogamic paleobotany

I use this phrase loosely, to refer to studies of fossils other than vascular plants: bryophytes, as well as fungi, lichens, algae and prokaryotes. The fossil record of these groups is much sparser than that of vascular plants, so work aimed at detailed characterization and taxonomic placement of new fossils is important for closing the gap. We described Early Silurian (Llandovery, ca. 440 Ma) cyanobacterial colonies with associated bacteria from terrestrial biotas of the Massanutten Sandstone in Virginia. Work in the lab currently focuses mainly on Early Devonian and Early Cretaceous material.

  1. In the Early Devonian Beartooth Butte Formation of Wyoming we are characterizing Lochkovian – Pragian (ca. 411 Ma) thalloid compression fossils that could be among the oldest thalloid liverworts. The Beartooth Butte Formation also hosts, in Emsian layers (407-395 Ma), Sphondylophyton, a fossil we recently reinterpreted as a red alga.

  2. Many projects in the lab concentrate on Eocene (ca. 45 Ma) and Early Cretaceous (Valanginian, ca. 136 Ma) material from Vancouver Island (British Columbia), as part of a collaboration with Gar Rothwell and Ruth Stockey’s lab at Oregon State University. This material shows exquisite cellular preservation and has yielded diaporthalean perithecial ascomycetes and chlorolichens. More important, the Early Cretaceous of Vancouver Island hosts the most diverse fossil bryophyte flora worldwide, which we are currently characterizing.

  3. Recent exploration of another Early Cretaceous unit from the western coast of North America, the Budden Canyon Formation of California, has revealed a richness of anatomically preserved fossil bryophytes matching that of the slightly older Vancouver Island material. Studies of this flora are also underway.

Origin of land plants

Fossil assemblages representing terrestrial communities of thalloid organisms similar to modern biological soil crusts span the Late Ordovician through Late Silurian (450-425 Ma) and are scattered throughout the Appalachian Basin (notably Virginia, West Virginia, Maryland, Pennsylvania, New York). These assemblages, younger than the earliest land plant spores but pre-dating the oldest known vascular plants, are important in the search for the oldest land plants.

Just like modern biological soil crusts, the Appalachian pre-tracheophyte communities were associations of different types of organisms, as demonstrated by: (1) diverse types of internal organization seen in individual thalloid fossils from the Early Silurian (Llandovery, ca. 440 Ma) Massanutten Sandstone of Virginia; (2) experiments that simulate fossilization on modern thalloid organisms producing structures similar to those of the Appalachian fossils in algae, fungi, lichens and bryophytes; (3) colonies of filamentous cyanobacteria we described in the Massanutten Sandstone; and (4) stable carbon isotope ratios that support terrestrial origin of the fossils and suggest that some of these were liverworts.

Current efforts focus on a Late Ordovician (Katian, ca. 450 Ma) sequence at Conococheague Mountain, in Pennsylvania, to refine a method for distinguishing between nearshore marine and continental deposits based on carbon and sulfur chemistry.

Plant morphological evolution

I am interested in the evolution of the basic features of the sporophyte body plan: indeterminate growth and branching, leaves, roots, radial patterning of tissues/boundary layers, vascular architecture. We approach questions in this area from two angles: the fossil record and the evolution of development as reflected by comparative anatomy.

  1. The lycopsid material in the Early Devonian (Lochkovian – Pragian, ca. 411 Ma) Beartooth Butte Formation of Wyoming represents one of the oldest plants with leaves and roots. Ongoing work on this plant is aimed at documenting in detail the rooting structures and whole-plant reconstruction. This work is combined with studies of rooting structures preserved in growth position, which provide insights into the three-dimensional architecture and growth patterns of the earliest rooting systems.

  2. Boundary layers form a sleeve of tissue continuous throughout the plant body, which separates vascular tissues from ground tissues. The endodermis, starch sheath and leaf vein bundle sheaths are different expressions of this boundary domain; in seed plants their specification seems to be controlled by a common regulatory mechanism. Considerably less is known about the development and specification of boundary layers outside the seed plants. We characterize the patterns of cell division leading to development of the endodermis and compare them across tracheophyte lineages, seeking a better understanding of the evolution of the stem-leaf-root body plan.

  3. The architecture of mature vascular tissues is determined by the development and architecture of the procambium in the apical meristems. Ongoing work is aimed at characterizing procambial architecture in different tracheophyte lineages, in search of shared patterns and phylogenetic signals, and to gain a clearer understanding of the evolution of steles and the stem-leaf-root body plan.

Paleobotany of Northern California

The exquisite permineralized floras of the Early Cretaceous and Eocene of Vancouver Island have counterparts in California. We are working in the Early Cretaceous (Barremian-Aptian, ca. 125 Ma) Budden Canyon Formation of northern California to document a rich permineralized flora. To date, we have identified pinaceous and cupressaceous conifers, ferns and bryophytes, and studies are underway to characterize in detail several of these plants. Additional field collecting is bound to reveal more diversity.

Fossil floras of Patagonia

Argentinian Patagonia is host to numerous fossil floras covering a very broad stratigraphic range. We are collaborating with scientists at Museo Paleontologico Egidio Feruglio in Trelew to characterize plants in several of these floras. Ongoing studies focus on ferns, sphenopsids and arborescent lycopsids of the Early Permian (ca. 290 Ma) Rio Genoa Formation, as well as Jurassic and Eocene ferns (dipterids) and bryophytes.


People

Mihai Tomescu

Professor of Botany

Drinks coffee, tea and yerba mate all day and keeps the lab running

Curriculum vitae

Alex Bippus

Graduate Student

Research interests: Phylogenetic relationships of early tracheophytes; fossil mosses and thalloid gametophytes; fossil evidence of early life; diversity of the Early Cretaceous bryoflora of Vancouver Island (Canada); fern leaf development; playing a diveristy of musical instruments...

Jessica Chu

Graduate Student

Research interests: Early Devonian permineralized floras - cladoxylopsids

Ashley Kammet

Graduate Student

Research interests: The seed cones of Cupressaceae - anatomy and morphology

Selin Toledo

Graduate Student

Research interests: Early Devonian permineralized floras - progymnosperms

Adolfina Savoretti

Collaborator - Graduate Student at Universidad Nacional de La Plata & Instituto de Botánica Darwinion, Argentina

Research interests: Bryophytes - systematics and fossil record

Shayda Abidi

Undergraduate

Research interests: Hydropteridalean ferns - Marsileaceae: fossil and extant

Maya Bickner

Undergraduate

Research interests: Early Devonian permineralized floras - euphyllophytes

Shanelle Dorn

Undergraduate

Research interests: Devonian microconchid encrusters

Samar El-Abdallah

Undergraduate

Research interests: Histological microtechnique, anatomy, Cupressaceae seed cones

Crystal Hofer

Undergraduate

Research interests: Early Devonian permineralized floras - woody plants

Kelly Pfeiler

Undergraduate

Research interests: Early Devonian permineralized floras - woody plants & rhyniophytes


Alumni

Jeffery Barrett, MSc

Working with extant plants as a botanist with California State Parks, but never forgetting the ancient glory of fossil plants

Allison Bronson

New York, New York

PhD student at the Richard Gilder Graduate School, American Museum of Natural History

Jamie Burnett

At large

Joey Caruso

At large

Alana Chin (Oldham), MSc

Davis, California

PhD student at the University of California - Davis, Department of Plant Sciences, in Maciej Zwieniecki's lab

Nevin Cullen

San Francisco, California

MSc student at San Francisco State University, Department of Biology, soon to enter the PhD program in Biological Sciences at the University of Pittsburgh

Melissa Dattola

Sonoma, Califonia

Emma Fryer

Fresno, California

Consultant biologist/environmental engineer – CalTrans

Lucas Henderson

Spokane, Washington

Forestry and Fire Ecologist – Kalispel Natural Resources Department

Laurel Hoffman

Corvallis, Oregon

Entering the PhD program in Plant Breeding and Genetics at Oregon State University

Kolby Lundgren

Humboldt County, California

Watershed Steward / Americorps – California Department of Fish & Wildlife

Kelly Matsunaga, MSc

Ann Arbor, Michigan

PhD student at the University of Michigan, Department of Earth & Environmental Sciences, in Selena Smith's lab

Shauna McDonald

East Bay area, California

P G & E

Hollister Nadeau

Sonoma County, California

Working toward a teaching credential

Ashley Ortiz

Humboldt County, California

Alaina Petlewski

Ithaca, New York

PhD student at Cornell University, School of Integrative Plant Science

Glenn Shelton, MSc

At large

Christopher Steenbock

Boulder, Colorado

PhD student at the University of Colorado, Department of Ecology and Evolutionary Biology

Richard Tate

Gainesville, Florida

PhD student at the University of Florida, School of Natural Resources and Environment

Christa Unger

Fresno, California

USDA - forest ecology


Lab Awards and Honors

2018

Dennis K. Walker Award—Humboldt State University, Dept. of Biological Sciences

Kelly Pfeiler

Patricia O. McConkey Outstanding Graduate Student Award—Humboldt State University

Alexander Bippus

2017

GSA Research Award—Geological Society of America

Selin Toledo

Maynard Moseley Award—Best student paper—Botanical Society of America, Paleobotanical and Developmental & Structural Sections

Maya Bickner

Kenneth E. & Annie Caster Student Research Award—Paleontological Society

Kelly Pfeiler & Shayda Abidi

Mid-American Paleontology Society Outstanding Student Research Award—Paleontological Society

Crystal Hofer

BSA Undergraduate Research Award—Botanical Society of America

Kelly Pfeiler

IAPT Research Award—International Association of Plant Taxonomists

Adolfina Savoretti

Rumble Botany Award—Humboldt State University, Dept. of Biological Sciences

Selin Toledo

Dennis K. Walker Award—Humboldt State University, Dept. of Biological Sciences

Alaina Petlewski

2016

Graduate Research Fellowship—National Science Foundation

Alexander Bippus

Maynard Moseley Award—Best student paper—Botanical Society of America, Paleobotanical and Developmental & Structural Sections

Alexander Bippus

Alistair & Judith McCrone Graduate Fellowship—Humboldt State University

Alexander Bippus

Graduate Student Research Award—Botanical Society of America

Adolfina Savoretti & Alexander Bippus

Stephen J. Gould Student Research Award—Paleontological Society

Selin Toledo

Kenneth E. & Annie Caster Student Research Award—Paleontological Society

Adolfina Savoretti

G. Arthur Cooper Student Research Award—Paleontological Society

Alexander Bippus

GSA Research Award—Geological Society of America

Selin Toledo

ASPT Research Award—American Society of Plant Taxonomists

Adolfina Savoretti

Gregory M. Jennings Graduate Botany Award—Humboldt State University, Dept. of Biological Sciences

Alexander Bippus

Dennis K. Walker Award—Humboldt State University, Dept. of Biological Sciences

Emma Fryer

F.R. Meredith Botany Scholarship—Humboldt State University, Dept. of Biological Sciences

Alaina Petlewski

Sterling Sam Award—Humboldt State University, Dept. of Biological Sciences

Kara Frampton

2015

GSA Research Award—Geological Society of America

Jessica Chu

Patricia O. McConkey Outstanding Graduate Student Award—Humboldt State University

Kelly Matsunaga

BSA Undergraduate Research Award—Botanical Society of America

Alexander Bippus

Young Botanist Award—Botanical Society of America

Kolby Lundgren & Christa Unger

Vernon I Cheadle Travel Award—Botanical Society of America

Jessica Chu

Rumble Botany Award—Humboldt State University, Dept. of Biological Sciences

Kelly Matsunaga

Dennis K Walker Award—Humboldt State University, Dept. of Biological Sciences

Kolby Lundgren

F.R. Meredith Botany Scholarship—Humboldt State University, Dept. of Biological Sciences

Kelly Pfeiler

Sterling Sam Award—Humboldt State University, Dept. of Biological Sciences

Ashley Ortiz

2014

Isabel Cookson Award—Best student paper—Botanical Society of America, Paleobotanical Section

Kelly Matsunaga

GSA Research Award—Geological Society of America

Kelly Matsunaga

James M. and Thomas J.M. Schopf Student Research Award—Paleontological Society

Kelly Matsunaga

Young Botanist Award—Botanical Society of America

Allison Bronson & Jamie Burnett

F.R. Meredith Botany Scholarship—Humboldt State University, Dept. of Biological Sciences

Alexander Bippus

University of Chicago—NSF Reserch Experience for Undergraduates (Malamy Lab)

Alexander Bippus

Alaska SeaLife Center Internship—Seward, Alaska

Nevin Cullen

2013

Graduate Student Research Award—Botanical Society of America

Kelly Matsunaga

Young Botanist Award—Botanical Society of America

Laurel Hoffman

Vernon I. Cheadle Travel Award—Botanical Society of America

Kelly Matsunaga

American Musuem of Natural History—NSF Reserch Experience for Undergraduates (Maisey Lab)

Allison Bronson

Academic Excellence and Achievement Award—College of Natural Resources and Sciences, Humboldt State University

Christopher Steenbock

Academic Excellence and Achievement Award—Best Undergraduate Research Project, Humboldt State University

Alexander Bippus & Maria Friedman

Academic Excellence and Achievement Award—Best Professional Publication, Humboldt State University

Allison Bronson

Academic Excellence and Achievement Award—Best Professional Presentation, Humboldt State University

Christa Unger

Gregory M. Jennings Graduate Botany Award—Humboldt State University, Dept. of Biological Sciences

Kelly Matsunaga & Glenn Shelton

Dennis K. Walker Award—Humboldt State University, Dept. of Biological Sciences

Christopher Steenbock

Sterling Sam Award—Humboldt State University, Dept. of Biological Sciences

Christa Unger

2012

Maynard Moseley Award—Best student paper—Botanical Society of America, Paleobotanical and Developmental & Structural Sections

Alexander Bippus and Maria Friedman

Young Botanist Award—Botanical Society of America

Kelly Matsunaga, Glenn Shelton, and Christopher Steenbock

Academic Excellence and Achievement Award—Best undergraduate research project, Humboldt State University

Kelly Matsunaga

Vernon I. Cheadle Travel Award—Botanical Society of America

Allison Bronson

Sterling Sam Award—Humboldt State University, Dept. of Biological Sciences

Christopher Steenbock

2011

Academic Excellence and Achievement Award—Best professional publication, Humboldt State University

Christopher Steenbock

Triarch Botanical Images Travel Award—First Place, Botanical Society of America

Glenn Shelton

Developmental & Structural Section Travel Award —Botanical Society of America

Kelly Matsunaga

2009

Young Botanist Award—Botanical Society of America

Lucas Henderson

Eureka Sequoia Garden Club Award—Promising Botany Student

Christopher Steenbock

2008

Katherine Esau Award—Best student paper—Botanical Society of America, Developmental & Structural Section

Alana Chin (Oldham)

Young Botanist Award—Botanical Society of America

Shauna McDonald

2007

Young Botanist Award—Botanical Society of America

Richard Tate

2006

Young Botanist Award—Botanical Society of America

Alana Chin


Publications

Student authors in bold face

  • Bippus AC, Escapa IH, Tomescu AMF 2018. Wanted dead or alive (probably dead): stem group Polytrichaceae. American Journal of Botany. in press
  • Toledo S, Bippus AC, Tomescu AMF 2018. Buried deep behind the veil of extinction: euphyllophyte relationships at the base of the spermatophyte clade. American Journal of Botany. in press
  • Savoretti A, Bippus AC, Stockey RA, Rothwell GW, Tomescu AMF 2018. Grimmiaceae in the Early Cretaceous: Tricarinella crassiphylla gen. et sp. nov. and the value of anatomically-preserved bryophytes. Annals of Botany. doi: 10.1093/aob/mcy015 PDF
  • Rothwell GW, Tomescu AMF 2018. Structural fingerprints of development at the intersection of evolutionary developmental biology and the fossil record. In Nuño de la Rosa L, Müller GB (eds) Evolutionary developmental biology – A reference guide. Springer. doi: 10.1007/978-3-319-33038-9_169-1 PDF
  • Pfeiler KC, Tomescu AMF 2018. An Early Devonian permineralized rhyniopsid from the Battery Point Formation of Gaspé (Canada). Botanical Journal of the Linnean Society. doi: 10.1093/botlinnean/boy011 PDF
  • Matsunaga KKS, Tomescu AMF 2018. Reciprocal illumination and fossils provide important perspectives in plant evo-devo: examples from auxin in seed-free plants. In Fernández H (ed.) Current advances in fern research. Springer. doi: 10.1007/978-3-319-75103-0_10 PDF
  • Tomescu AMF, Bomfleur B, Bippus AC, Savoretti A 2018. Why are bryophytes so rare in the fossil record? A spotlight on taphonomy and fossil preservation. In Krings M, Harper CJ, Cúneo NR, Rothwell GW (eds) Transformative paleobotany: Papers to commemorate the life and legacy of Thomas N. Taylor. Elsevier. in press
  • Tomescu AMF, Escapa IH, Rothwell GW, Elgorriaga A, Cuneo NR 2017. Developmental programmes in the evolution of Equisetum reproductive morphology: a hierarchical modularity hypothesis. Annals of Botany 119, 489–505. PDF
  • Matsunaga KKS, Cullen NP, Tomescu AMF 2017. Vascularization of the Selaginella rhizophore – anatomical fingerprints of polar auxin transport with implications for the deep fossil record. New Phytologist 216, 419-428. PDF
  • Matsunaga KKS, Tomescu AMF 2017. An organismal concept for Sengelia radicans gen. et sp. nov. – morphology and natural history of an Early Devonian lycophyte. Annals of Botany 119, 1097-1113. PDF Journal issue cover
  • Bippus AC, Stockey RA, Rothwell GW, Tomescu AMF 2016. Extending the fossil record of Polytrichaceae: Early Cretaceous Meantoinea alophosioides gen. et sp. nov., permineralized gametophytes with gemma cups from Vancouver Island. American Journal of Botany 104, 584-597. PDF Journal issue cover
  • Burnett JK, Fryer ER, Unger CR, Tomescu AMF 2016. Pinaceous wood from the Lower Cretaceous (Barremian–lower Aptian) of California, USA – Lower Chickabally Member, Budden Canyon Formation. Ameghiniana 53, 685-694. PDF
  • Tomescu AMF 2016. The Early Cretaceous Apple Bay flora of Vancouver Island: a hotspot of fossil bryophyte diversity. Botany 94, 683-695. PDF
  • Shelton GWK, Stockey RA, Rothwell GW, Tomescu AMF 2016. Krassiloviella limbelloides gen. et sp. nov.: additional diversity in the pleurocarpous moss family Tricostaceae (Valanginian, Vancouver Island, British Columbia). International Journal of Plant Sciences 177, 792-808. PDF
  • Tomescu AMF 2016. Development: paleobotany at the high table of evo-devo. Current Biology 26, R505-508. PDF
  • Tomescu AMF, Klymiuk AA, Matsunaga KKS, Bippus AC, Shelton GWK 2016. Microbes and the fossil record - selected topics in paleomicrobiology. In Hurst CJ (ed.) Advances in environmental microbiology. Vol. 1. Their world: a diversity of microbial environments, p. 69-169. Springer, Heidelberg. PDF
  • Matsunaga KKS, Tomescu AMF 2016. Root evolution at the base of the lycophyte clade - insights from an Early Devonian lycophyte. Annals of Botany 117, 585-598. PDF
  • Shelton GWK, Stockey RA, Rothwell GW, Tomescu AMF 2015. Exploring the fossil history of pleurocarpous mosses: Tricostaceae fam. nov. from the Cretaceous of Vancouver Island, Canada. American Journal of Botany 102, 1883-1900. PDF Journal issue highlights
  • Rothwell GW, Wyatt SE, Tomescu AMF 2014. Plant evolution at the interface between paleontology and developmental biology: an organism centered paradigm. American Journal of Botany 101, 899-913. PDF Journal issue cover
  • Tomescu AMF, Wyatt SE, Hasebe M, Rothwell GW 2014. Early evolution of the vascular plant body plan - the misssing mechanisms. Current Opinion in Plant Biology 17, 126-136. PDF
  • Steenbock CM, Tomescu AMF 2013. Resurrecting Sphondylophyton as a rhodophyte alga from the Early Devonian. International Journal of Plant Sciences 174, 1171-1181. PDF
  • Hoffman LA, Tomescu AMF 2013. An early origin of secondary growth: Franhueberia gerriennei gen. et sp. nov. from the Lower Devonian of Gaspe (Quebec, Canada). American Journal of Botany 100, 754-763. PDF
  • Bronson AW, Klymiuk AA, Stockey RA, Tomescu AMF 2013. A perithecial sordariomycete (Ascomycota, Diaporthales) from the Lower Cretaceous of Vancouver Island, British Columbia (Canada). International Journal of Plant Sciences 174, 278-292. PDF Journal issue cover
  • Matsunaga KKS, Stockey RA, Tomescu AMF 2013. Honeggeriella complexa gen. et sp. nov., a heteromerous lichen from the Lower Cretaceous of Vancouver Island (British Columbia, Canada). American Journal of Botany 100, 450-459. PDF
  • Zaton M, Vinn O, Tomescu AMF 2012. Invasion of freshwater and variable marginal marine habitats by microconchid tube worms - an evolutionary perspective. Geobios 45, 603-610. PDF
  • Caruso JA, Tomescu AMF 2012. Microconchid encrusters colonizing land plants: the oldest North American record from the Early Devonian of Wyoming, USA. Lethaia 45, 490-494. PDF
  • Steenbock CM, Stockey RA, Beard G, Tomescu AMF 2011. A new family of leafy liverworts from the middle Eocene of Vancouver Island, British Columbia, Canada. American Journal of Botany 98, 998-1006. PDF
  • Tomescu AMF 2011. The sporophytes of seed-free vascular plants – major vegetative developmental features and molecular genetic pathways. Pp. 67-94 in Fernandez H, Kumar A, Revilla MA (eds) Working with ferns: issues and applications. Springer, Berlin. PDF
  • Tomescu AMF, Tate RW, Mack NG, Calder VJ 2010. Simulating fossilization to resolve the taxonomic affinities of thalloid fossils in Early Silurian (ca. 425 Ma) terrestrial assemblages. Bibliotheca Lichenologica 105, 183–189. Biology of lichens – symbiosis, Ecology, environmental monitoring, systematics, cyber applications. Nash TH III et al. (eds). J.Cramer/Gebruder Borntraeger Verlagsbuchhandlung, Stuttgart. PDF
  • Oldham AR, Sillett SC, Tomescu AMF, Koch GW 2010. The hydrostatic gradient, not light availability, drives height-related variation in Sequoia sempervirens (Cupressaceae) leaf anatomy. American Journal of Botany 97, 1087-1097. PDF
  • Tomescu AMF, Pratt LM, Rothwell GW, Strother PK, Nadon GC 2009. Carbon isotopes support the presence of extensive land floras pre-dating the origin of vascular plants. Palaeogeography Palaeoclimatology Palaeoecology 283, 46-59. PDF
  • Tomescu AMF, Rothwell GW, Honegger R 2009. A new genus and species of filamentous microfossil of cyanobacterial affinity from Early Silurian fluvial environments (lower Massanutten Sandstone, Virginia, USA). Botanical Journal of the Linnean Society 160, 284-289. PDF
  • Tomescu AMF 2009. Megaphylls, microphylls and the evolution of leaf development. Trends in Plant Science 14, 5-12. PDF Journal issue cover
  • Tomescu AMF, Rothwell GW, Trivett ML 2008. Reiterative growth in the complex adaptive architecture of the Paleozoic (Pennsylvanian) filicalean fern Kaplanopteris clavata. Plant Systematics and Evolution 270, 209-216. PDF
  • Tomescu AMF 2008. The endodermis: a horsetail's tale. New Phytologist 177, 291-295. PDF
  • Tomescu AMF, Honegger R, Rothwell GW 2008. Earliest fossil record of bacterial-cyanobacterial mat consortia: the early Silurian Passage Creek biota (440 Ma, Virginia, USA). Geobiology 6, 120-124. PDF
  • Tomescu AMF 2007. On divides. Taxon 56, 289-291. PDF
  • Tomescu AMF, Rothwell GW, Honegger R 2006. Cyanobacterial macrophytes in an Early Silurian (Llandovery) continental biota: Passage Creek, lower Massanutten Sandstone, Virginia, USA. Lethaia 39, 329-338. PDF
  • Tomescu AMF 2006. Comment [and reply] on Something on the side: axillary meristems and plant development, by Tom Bennett and Ottoline Leyser. Plant Molecular Biology 60, 481-482. PDF
  • Tomescu AMF, Rothwell GW, Trivett ML 2006. Kaplanopteridaceae fam. nov., additional diversity in the initial radiation of filicalean ferns. International Journal of Plant Sciences 167, 615-630. PDF
  • Tomescu AMF, Rothwell GW 2006. Wetlands before tracheophytes: thalloid terrestrial communities of the Early Silurian Passsage Creek biota (Virginia). In Greb SF, DiMichele WA (eds) Wetlands through time. Geological Society of America Special Paper 399, 41-56. PDF
  • Tomescu AMF 2005. Probing the seasonality signal in pollen spectra of Eneolithic coprolites (Harsova-tell, Constanta County, southeast Romania). Culture and Civilization on the Lower Danube (Cultura si Civilizatie la Dunarea de Jos, Calarasi, Romania) 22, 207-221. PDF
  • Tomescu AMF, Rothwell GW 2004. First steps on land - organismal evolution in early terrestrial biotas. 7th International Organization of Paleobotany Conference (Bariloche, Argentina), 125-127. PDF
  • Tomescu M, Ticleanu N, Stoian L 2003. La palynologie des depots Romaniens du Bassin Dacique (en Roumanie). Chronostratigraphie und Neostratotypen. Neogene der Zentrale Paratethys 10. PL2 Romanien. Romanian Academy of Sciences. PDF
  • Tomescu AMF, Radu V, Moise D 2003. High resolution stratigraphic distribution of coprolites within Eneolithic middens, a case study: Harsova-tell (Constanta County, southeast Romania). Environmental Archaeology 8, 97-109. PDF
  • Tomescu AMF, Rothwell GW, Mapes G 2001. Lyginopteris royalii sp. nov. from the Upper Mississippian of North America. Review of Paleobotany and Palynology 116, 159-173. PDF
  • Tomescu AMF 2000. Evaluation of Holocene pollen records from the Romanian Plain. Review of Palaeobotany and Palynology 109, 219-233. PDF


Teaching

General Botany — BOT 105

Structure, function, reproduction, ecology, interactions and phylogenetic relationships of plant, fungal and protist groups.

Developmental Plant Anatomy — BOT 322/522

Plant structure and development – descriptive anatomy and molecular mechanisms; emphasis on seed plants and angiosperms.

Evolutionary Morphology of Plants — BOT 372/572

Organismal biology, phylogeny and evolution of vascular plants; phylogenetics – theory and applications.

Paleobotany — BOT 521

Fossil record of plant, fungal and protist groups; fossil formation, chronostratigraphy and implications for evolution and phylogeny; lab techniques.


Prospective Students

Scientific research is a way of life, not a job (although the luckier of us get paid to do it). It may or may not be your way of life and that’s just fine, either way. If it is, it will always bring excitement, novelty and accomplishment in your life (although data collecting is admittedly often monotonous and sometimes tedious) and will keep you happy. If it isn’t your way of life, it will just seem tedious and dreary and you should look for something better to do that will make you happy.

What students do

Graduate and undergraduate students are conducting research in my lab. Many of these students present their results at national and international meetings and quite a few have published in journals such as the American Journal of Botany and the International Journal of Plant Sciences.

Projects usually involve anatomic and morphological characterization of fossil and extant plants; comparative morphology, anatomy and development; extensive surveys of the primary literature on plant anatomy, morphology, systematics, and fossil record; taxonomic treatments. Sometimes we organize field trips to collect fossils.

Students learn and employ techniques for processing fossil plant material (cellulose acetate peel technique, rock thin sectioning, degagement), as well as fresh material (microtechnique – paraffin embedding, microtome sectioning, staining); digital image capture and processing; morphometric measurements. They also pick up bits and pieces of geology (petrology, sedimentology, stratigraphy) and phylogenetics. Some use electron microscopy, some run exhaustive searches of the literature (online databases) on selected topics, and all students read a lot.

Undergraduate Students

Many undergraduate students approach me about working on projects with me to build some research experience. If you are one of those students, please consider the following:

  • This is volunteer work. If you do it well and enough, it may earn you a strong letter of recommendation (for internships, graduate schools, awards, etc.), a line to strengthen your resume/curriculum vitae, and even the opportunity to give a presentation at a science meeting or a publication.

  • Look at the lab’s research page to see if you are interested in the research directions that we are addressing.

  • Your major, academic level or GPA matter less. What matters much more is your level of interest and commitment.

  • If you are unable to commit at least 2-3 hours per week to a research project on a consistent basis (that is, irrespective of exams, homework etc.), the effort is not worth your time (nor mine) since it won’t gather the momentum needed to produce meaningful data and results.

  • Willingness to learn, attention to detail, good organizational skills and reliability are essential requisites; additionally, a certain level of obsessive compulsion has never hurt anybody doing research. Conversely, lack of organization or attention to detail sooner or later lead to loss of painstakingly acquired data or destruction of unique research specimens and are unwelcome.

  • Serious research requires more than going through the moves of working with specimens and acquiring the raw data (a lab technician can do that). It requires thinking and reading on your own about your project, asking yourself and others questions about it, in short, making it a part (and an important one at that!) of your intellectual life.

This brings me to my view of undergraduate research:

  • I see undergraduate involvement in research as reaching one of two levels: lab tech and investigator. At the lab tech level (the minimum 2-3 hrs/week), students will produce a significant amount of data but may not take the next step to interpret them and produce results; their work will nevertheless be acknowledged when results based on those data are presented or published.
  • To reach the investigator level, students have to be involved in their project much more seriously. This implies more time and thought dedicated to it, as well as independent work. Work this hard will produce results that are presentable at a science meeting. If you are one of these students, I will help you present your results and, if appropriate, publish them.

Graduate Students

I will gladly address inquiries into the possibility of conducting graduate studies under my direction. If you are a prospective graduate student, please consider the following:

  • Our program only offers the Master of Science/Master of Arts options.

  • You should contact the head of the graduate program for our department, Dr. Erik Jules, and the graduate coordinator, Ms. Elizabeth Weaver, to get information about the workings of the program, financial and other.

  • I usually draw graduate thesis projects from work that is developing the different directions of my research program. I am, nevertheless, open to the prospective graduate student’s original ideas as long as the research involved falls within the realm of my expertise.

I expect a few things from graduate students. In no particular order, these are:

  1. To be curious, self-motivated and quickly become independent workers who actively seek my advice (as opposed to lab dwellers waiting for orders).

  2. To be good critical thinkers.

  3. To have good organizational skills and excellent attention to detail; these are crucial in successfully addressing the tedium of data collection and management, as well as in presenting the results of research, orally or in writing.

  4. To be or become well-trained in plant organismal biology, morphology, anatomy, development, and the fossil record.

  5. To be proficient at searching the literature (available online or otherwise) and building comprehensive summaries of research findings and state-of-the-art knowledge in their particular direction of investigation and closely related fields.


Dr. Mihai Tomescu
Office Science A 360
Phone (707) 826-3229
mihai@humboldt.edu
Department of Biological Sciences
Humboldt State University
1 Harpst Street
Arcata, California 95521

Web design: C. M. Steenbock

Last updated: 5 April 2018