Contact Information:

Kathleen Pryer
Department of Biology
Duke University
Durham, NC 27707-0338
Telephone: 919-660-7380
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Carl Rothfels, Ph.D.


I'm doing a postdoc with Sally Otto, at UBC, but can still be reached via the Pryer lab.



B.Arts & Science, Comb. Honours Biology. McMaster University, Hamilton, ON. Canada.

Ph.D. 2012. Duke University, Durham NC. USA.


My CV is available here. Here, also, is my Google Scholar profile.

Dissertation Research

I'm interested in investigating multiple elements of diversification (molecular divergence, morphological disparity, macroevolution) using species-level phylogenetics—a "process" approach. I'm also interested in integrating a broad spectrum of data (ecological, phylogenetic, cytological, morphological, etc.) into a cohesive taxonomic understanding of a group—the "pattern" approach.

Within the pattern/process framework outlined above, I’m seeking to develop an empirical dataset to evaluate the long-term evolutionary potential of polyploids (taxa with more than the typical two complete sets of chromosomes). Polyploidy is a common, widespread phenomenon, especially in plants, and there is an extensive literature on both the prevalence of new polyploids (polyploid formation) and on the existence of polyploid ancestors deep in the tree of life. The new polyploids demonstrate that this seemingly unlikely mutation (doubling of chromosome sets) occurs relatively frequently; the ancient polyploid ancestors (paleopolyploids) show that polyploid lineages can, at least occasionally, diversify into large clades (including the vertebrates, and the angiosperms).

What we are lacking, however, is an understanding of the general evolutionary fate of polyploid taxa. Do they tend to go extinct quickly (and are thus “evolutionary noise”) or do they comprise potent material for future diversification and the generation of evolutionary novelty? Given the prevalence of extant polyploids today, this question has profound implications for our understanding of planetary biodiversity.

This question is additionally interesting/fun/intimidating because it resides at the intersection of a number of phylogenetic challenges. Most polyploids involve reticulate patterns of evolution, and thus their history cannot be fully represented by the classic bifurcating evolutionary tree. And chromosome number evolves according to mathematical relationships not incorporated in classic ancestral character state reconstruction methods. And the state of being polyploid may influence a lineage’s propensity to diversify, and thus the character state reconstructions and “tree” inference need to be performed simultaneously. And so on.

I'm whittling away at these issues using low-copy nuclear sequence data from the fern genus Cystopteris, a genus of some 20 – 30 species, is a legendary taxonomic and evolutionary bugbear (at least within fern circles), blessed with rampant polyploidy. Much of the confusion surrounds a single named taxon—Cystopteris fragilis—that, as typically circumscribed, occurs on every continent save Antarctica, and at ploidy levels ranging from diploid (two chromosome sets) to octaploid (eight sets).

My eternal gratitude, then, to any hardy souls who are willing and able to send me Cystopteris (or Gymnocarpium, or Acystopteris, or Cystoathyrium) specimens from across their range. If you might be in this category, please let me know and we can negotiate (and I can describe the sorts of material that are particularly helpful.)

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A smattering of Cystopteris.... (including protrusa, membranifolia, and hexaploid fragilis from Utah)

The focus of my dissertation aside, I have past and present research interests in a number of other questions, including:

Deep phylogeny and taxonomy of Eupolypods II. Eupolypods II is a large clade, encompassing nearly 1/3 of extant fern species, including Cystopteris and its relatives. The relationships among eupolypod II taxa have been a source of great contention, apparently due to complex patterns of morphological evolution, and an ancient rapid radiation at the base of the clade.

Taxonomy and evolution of Notholaena and related taxa (cheilanthoids: Pteridaceae), a group notable for its ability to colonize deserts and other extremely harsh, ostensibly fern-unfriendly habitats. Nearly all Notholaena species have the undersides of their leaves covered with a brightly colored wax-like deposit (farina), which poses interesting research challenges both in terms the evolution of this feature and the taxonomic significance of the differently colored chemotypes that frequently occur within a single named species.

Heterogeneous rates of evolution within the adiantoids (the "vittarioids" plus Adiantum; also in the Pteridaceae). This clade is perhaps most notable for its coincidence of great morphological disparity (members of Adiantum and the vittarioids have dramatically different gross morphology and ecology; the former is a genus of understory species, while the latter are almost exclusively epiphytes) and a great difference in rates of molecular evolution (much faster in the vittarioids than inAdiantum). Relating and unraveling these factors may offer insight into the thorny (frondy?) intersection of micro and macroevolution.

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Some very fine Notholaena (incl. brevistipes looking very dessicated, candida, meridionalis, and ochracea)

Refereed Articles


Rothfels, C.J., and E. Schuettpelz. 2014. Accelerated rate of molecular evolution for vittarioid ferns is strong and not driven by selection. Systematic Biology 63(1): 31-54. doi:10.1093/sysbio/syt058. Reprint PDF
Sundue, M.A, and C.J. Rothfels. 2014. Stasis and convergence characterize morphological evolution in eupolypod II ferns. Annals of Botany 113(1): 35-54. doi:10.1093/aob/mct247. Reprint PDF



Rothfels C.J., A. Larsson, F.-W. Li, E.M. Sigel, L. Huiet, D.O. Burge, M. Ruhsam, S.W. Graham, D. Stevenson, G.K.-S. Wong, P. Korall, and K.M. Pryer. 2013. Transcriptome-mining for single-copy nuclear markers in ferns. PLoS ONE 8(10): e76957. doi:10:1371/journal.pone.0076957. Reprint PDF
León, B., C.J. Rothfels, M. Arakaki, K.R. Young, and K.M. Pryer. 2013.  Revealing a cryptic fern distribution through DNA sequencing: Pityrogramma trifoliata in the western Andes of Peru. American Fern Journal 103(1): 40-48. Reprint PDF
Rothfels, C.J., M.D. Windham, and K.M. Pryer. 2013. A plastid phylogeny of the cosmopolitan fern family Cystopteridaceae (Polypodiopsida). Systematic Botany 38(2): 295–306. Reprint PDF


Rothfels, C.J.*, M.A. Sundue*, L.Y. Kuo, A. Larsson, M. Kato, E. Schuettpelz, and K.M. Pryer. 2012. A revised family-level classification for eupolypod II ferns (Polypodiidae: Polypodiales). Taxon 61: 515-533. *equally contributing authors. Reprint PDF
Johnson, A.K., C.J. Rothfels, M.D. Windham, and K.M. Pryer. 2012. Unique expression of a sporophytic character on the gametophytes of notholaenid ferns (Pteridaceae). American Journal of Botany 99: 1118-1124. Reprint PDF
Rothfels, C.J., E.M. Sigel, and M.D. Windham. 2012. Cheilanthes feei T. Moore (Pteridaceae) and Dryopteris erythrosora (D.C. Eaton) Kunze (Dryopteridaceae) new for the flora of North Carolina. American Fern Journal 102(2): 184-186. Reprint PDF
Rothfels, C.J.*, A. Larsson*, L.-Y. Kuo*, P. Korall, W.-L. Chiou, and K.M. Pryer. 2012. Overcoming deep roots, fast rates, and short internodes to resolve the ancient rapid radiation of eupolypod II ferns. Systematic Biology 61: 490-509. doi: 10.1093/sysbio/sys001. *equally contributing. Reprint PDF (Cover)
Rothfels, C.J., E. Gaya, L. Pokorny, Paul Rothfels, Peter Rothfels, and G.R. Feulner. 2012. Five new records for the Arabian Peninsula and other significant fern, lichen and bryophyte collections from the UAE and northern Oman. Tribulus 20: 4-20. Reprint PDF


Li, F.-W., L.-Y. Kuo, C.J. Rothfels, A. Ebihara, W.-L. Chiou, M.D. Windham, and K.M. Pryer. 2011. rbcL and matK earn two thumbs up as the core DNA barcode for ferns. PLoS One 6: e26597. Reprint PDF
Mayrose, I, S.H. Zhan, C.J. Rothfels, K. Magnuson-Ford, L. Rieseberg, M.S. Barker, and S.P. Otto. 2011. Recently formed polyploid plants diversify at lower rates. Science 333: 1257. Reprint PDF
Galbraith, D.A., N.E. Iwanycki, B.V. McGoey, J. McGregor, J.S. Pringle, C.J. Rothfels, and T.W. Smith. 2011. The evolving role of botanical gardens and natural areas: A floristic case study from Royal Botanical Gardens, Canada. Plant Diversity and Resources 33(1): 123-131. Reprint PDF



Pryer, K.M., E. Schuettpelz, L. Huiet, A.L. Grusz, C.J. Rothfels, T. Avent, D. Schwartz, and M.D. Windham. 2010. DNA barcoding exposes a case of mistaken identity in the fern horticultural trade. Molecular Ecology Resources 10:979-985. Reprint PDF
Windham, M.D., L. Huiet, E. Schuettpelz, A.L. Grusz, C.J. Rothfels, J.B. Beck, G. Yatskievych, and K.M. Pryer. 2009. Using plastid DNA sequences to redraw generic boundaries in cheilanthoid ferns (Pteridaceae). American Fern Journal 99: 128-132. Reprint PDF
Rothfels, C.J., M.D. Windham, A.L. Grusz, G.J. Gastony, and K.M. Pryer. 2008. Toward a monophyletic Notholaena (Pteridaceae): Resolving patterns of evolutionary convergence in xeric-adapted ferns. Taxon 57(3): 712-724. Reprint PDF
Jaramillo, A., M.T.J. Johnson, C.J. Rothfels, and R.A. Johnson. 2008. The native and exotic avifauna of Easter Island: Then and now. Boletin Chileno de Ornitologia 14(1): 8-21. Reprint PDF
Rothfels, C.J. 2004. Significant vascular plant records from the Hamilton area, Ontario. Canadian Field-Naturalist 118(4): 612-615. Reprint PDF
Rothfels, C.J., L.L. Beaton, and S. Dudley. 2002. The effects of salt, manganese, and density on life history traits in Hesperis matronalis L. from oldfield and roadside populations. Canadian Journal of Botany 80: 131-139. Reprint PDF
Johnson, M.T. and C.J. Rothfels. 2001. The establishment and proliferation of the rare exotic plant, Lythrum hyssopifolia, (Hyssop-leaved Loosetrife), at a pond in Guelph, Ontario. Canadian Field-Naturalist 115(2): 229-233. Reprint PDF

Other Peer-reviewed Publications

Rothfels, C.J. and T.W. Smith. In review. Update COSEWIC report on Green Dragon, Arisaema dracontium. Committee on the Status of Endangered Wildlife in Canada, Ottawa.

Smith, T.W. and C.J. Rothfels. In review. Update COSEWIC report on Broad Beech Fern, Phegopteris hexagonoptera. Committee on the Status of Endangered Wildlife in Canada, Ottawa.

Waldron, G., C.J. Rothfels, J. Bowles, and Environment Canada. 2011. Recovery strategy for the Skinner’s Agalinis (Agalinis skinneriana) in Canada [Proposed]. Species at Risk Act Recovery Strategy Series. Environment Canada, Ottawa. v + 16 pp. Reprint PDF

Smith, T.W. and C.J. Rothfels. 2010. Recovery strategy for Few-flowered Club-rush (Trichophorum planifolium) in Ontario. Ontario Recovery Strategy Series. Prepared for the Ontario Ministry of Natural Resources, Peterborough, Ontario. ii + 4 pp. + Appendix vi + 22 pp. + addenda. Reprint PDF

Rothfels, C.J. and S.Y. Gibson. 2007. COSEWIC assessment and update status report on the round-leaved greenbrier (Great Lakes Plains and Atlantic population) Smilax rotundifolia in Canada. Committee on the Status of Endangered Wildlife in Canada, Ottawa. Reprint PDF

Smith, T.W. and C.J. Rothfels. 2007. Recovery strategy for Few-flowered Club-rush/Bashful Bulrush (Trichophorum planifolium (Sprengel) Palla) in Canada. Prepared for the Ontario Ministry of Natural Resources by Royal Botanical Gardens. Hamilton. vi + 22 pp. Reprint PDF

Smith, T.W., C.J. Rothfels, and E. Oberndorfer. 2006. COSEWIC assessment and update status report on the American Columbo Frasera caroliniensis in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 21 pp. ( Reprint PDF

Other Publications

Rothfels, Carl. 2008. Pteridaceae E.D.M. Kirchn. 1831. Brake Ferns, Maidenhair Ferns, and allies. in The Tree of Life Web Project,  [And approximately 30 nested pages].
Rothfels, Carl. 2007. The Comet Darner (Anax longipes: Aeshnidae): Possibly breeding in Canada. Ontario Odonata 7:38-41. Reprint PDF
Rothfels, Carl. 2007. Three years of the Hamilton odonate count. Ontario Odonata 7: 36-37. Reprint PDF
Rothfels, Carl. 2007. Odonata of Halton Region. Ontario Odonata 7: 33-35. Reprint PDF
Rothfels, Carl. 2007. Dense darner swarm in Algonquin Provincial Park: Observations and questions. Ontario Odonata 7: 43-48. Reprint PDF
Rothfels, C.J. 2007. Significant Hamilton Study Area plant records from the herbarium of Royal Botanical Gardens (HAM): 2005 (part 3). Wood Duck 60(5): 106-111.
Rothfels, C.J. 2006. The dragonflies and damselflies (Odonata) of Halton Region, Ontario. Pages 135-158 in: Halton Natural Areas Inventory 2006: Volume 2 Species Checklists. Hamilton Naturalists’ Club, Halton-North Peel Naturalists’ Club, and South Peel Naturalists’ Club. Hamilton, Ontario. Reprint PDF
Rothfels, C.J. 2006. Significant Hamilton Study Area plant records from the herbarium of Royal Botanical Gardens (HAM): 2005 (part 2). Wood Duck 60(4): 83-84.
Rothfels, C.J. 2006. Significant Hamilton Study Area plant records from the herbarium of Royal Botanical Gardens (HAM): 2005 (part 1). Wood Duck 60(3): 60-62.
Rothfels, C.J. 2006. Hamilton odonate count III: Zebras and spatterdocks. Wood Duck 60(1): 13-15. Reprint PDF
Rothfels, C.J. 2006. Significant Hamilton Study Area (HSA) odonate records from 2005. Wood Duck 59(9): 222-225. Reprint PDF
Van Ryswyk, B. and C.J. Rothfels. 2006. Significant 2005 odonate records from Halton Region. Wood Duck 59(8): 183-186. Reprint PDF
Rothfels, C.J. and W. Muma. 2006. Goldfinch killed by burdock. Wood Duck 59(7):151-152. Reprint PDF
Rothfels, C.J. 2006. One specimen, many stories. Now @ The Gardens. 3(1): 4-5. Reprint PDF
Rothfels, C.J. 2006. Heating up the sanctuaries: Gardens' prescribed burns 2006. Now @ The Gardens. 3(1): 7. Reprint PDF
Rothfels, C.J. 2005. Significant plant records from the herbarium of Royal Botanical Gardens (HAM): 2003. Field Botanists of Ontario Newsletter. 17(2): 7-12. Reprint PDF
Rothfels, C.J. 2005. Botanical diversions: The Latin name game. Field Botanists of Ontario Newsletter. 17(4): 12.
Rothfels, C.J. 2005. A Brown Widow (Lactrodectus geometricus) arrives in Burlington. Wood Duck. 59(4): 98. Reprint PDF
Rothfels, C.J. 2005. The second annual Hamilton odonate count. Wood Duck. 59(3): 53-55. Reprint PDF
Rothfels, C. 2005. American Columbo (Frasera caroliniensis) in the Cartwright Nature Sanctuary. Wood Duck. 59(1): 3-4. Reprint PDF
Rothfels, C.J. 2005. Significant 2004 Hamilton Study Area plant records from the Royal Botanical Gardens herbarium (HAM). Part II: Alphabetical families Lardizabalaceae to Vitaceae. Wood Duck. 58(9): 219-223. Reprint PDF
Rothfels, C.J. 2005. Significant 2004 Hamilton Study Area plant records from the Royal Botanical Gardens herbarium (HAM). Part I: Alphabetical families Aceraceae to Lamiaceae. Wood Duck. 58(8): 187-192. Reprint PDF
Welch, T. and C.J. Rothfels. 2005. Trumpeter swans (Cygnus buccinator) fledge young at The Gardens. Now @ The Gardens. 2(4). Reprint PDF
Scott, E. C. and C.J. Rothfels. 2005. Getting muddy for the marsh—marsh volunteer plantings 2005. Now @ The Gardens. 2(4).
Rivet, R. and C.J. Rothfels. 2005. York Boulevard Prairie prescribed burn 2005. Now @ The Gardens. 2(3).
Rothfels, C.J., T.Theysmeyer, and B.McKean. 2005. Rare fish found at the Fishway. Now @ The Gardens. 2(2).
Rothfels, C.J. 2005. Princess Point Earth Day planting. Now @ The Gardens. 2(2).
Rothfels, C.J. and P.M. Catling. 2005. Notes: Major dragonfly migration at Hamilton. Ontario Odonata. 6: 40. Reprint PDF
Rothfels, C.J. 2004. Unicorn Clubtail (Arigomphus villosipes: Gomphidae): New records and summary of status in Ontario. Ontario Odonata. 5: 5-11. Reprint PDF
Rothfels, C.J. 2004. Significant plant records from the herbarium of Royal Botanical Gardens (HAM): 2002. Field Botanists of Ontario Newsletter. 16(3): 7-12.
Rothfels, C.J. 2004. The First Annual Hamilton Odonate Count. Wood Duck. 58(2): 27-29. Reprint PDF
Rothfels, C.J., S. Spisani and J. Sylvester. 2004. Significant 2003 Hamilton Study Area plant records from the Royal Botanical Gardens herbarium (HAM). Wood Duck. 57(9): 213-219. Reprint PDF
Rothfels, C.J. 2004. Stoneflies’ Great-great-great-great Grandparents. Wood Duck. 57(8): 179.
Rothfels, C.J. 2004. Intrepid insects: Capniids in Cootes. Wood Duck. 57(7): 153-154. Reprint PDF
Rothfels, C.J. 2004. The beetle, the oak, the fire, and the future of our nature sanctuaries. Now @ The Gardens. 1(1).
Rothfels, C.J. 2003. Royal Botanical Gardens Odonate Count 2003Ontario Insects. 9(1): 11-13. Reprint PDF
Rothfels, C.J. 2003. Synopsis of Ontario herbaria. Field Botanists of Ontario Newsletter. 16(1): 7-19.
Rothfels, C.J. 2003. Field trip report: Yarmouth Natural Heritage Area. Field Botanists of Ontario Newsletter. 15(4): 7-9.
Rothfels, C.J. 2003. Royal Botanical Gardens odonate count 2003. Wood Duck. 57(1): 5-7.
Rothfels, C.J. 2003. Significant 2002 Hamilton Study Area plant records from the Royal Botanical Gardens herbarium (HAM). Wood Duck. 56(7): 155-161. Reprint PDF
Rothfels, C.J. 2002. Botanical Diversions: Salad taxonomy. Field Botanists of Ontario Newsletter. 15(1): 8-10.
Rothfels, C.J. 2002. Review: Lichen guides. Wood Duck. 56: 68.
Rothfels, C.J. 2002. Learning lichens from Ernie Brodo. Wood Duck. 56: 51-54.
Rothfels, C.J. 2002. Listening to whipbird duets in Australia. Wood Duck56: 21-22.
Rothfels, C.J. 2001. Doi Inthanon – A Hamilton Naturalist Abroad. Wood Duck. 55(3): 57-58.
Rothfels, C.J. and M.T. Johnson. 2000. Botany Excursions: Massassauga Point and Point Petre Wildlife Area, Prince Edward County. Field Botanists of Ontario Newsletter. 13(3): 6-10.
Rothfels, C.J. 1998. Birds of the Feather Band Together. Wood Duck. 51(7): 131-136.
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A complete fraud, of course.
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Mike Windham was a very support committee member.
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Some misc. fieldwork shots, featuring Amanda Grusz, Anemia, and Carex/Cymophyllus fraseri--the pride of the Appalachians
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Ninety-six small bits of Notholaena and Cystopteris about to get sacrificed to science.
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Plant (and pant) drying techinques
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Some quality roadside plant-pressing action, with Erin Sigel and Monique McHenry, in Ecuador
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The ever-so gorgeous (and genomically promiscuous?) Gymnocarpium appalachianum
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Dan Runcie distracting me with some tunicates on the coast of Oregon
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There must be a fern around here somewhere
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