Tom A. Ranker

Professor & Graduate Chair of Botany



PhD 1987, University of Kansas

Curriculum Vitae – Tom A. Ranker

Contact Information

Research Interests

The origin and evolution of the flora of the Hawaiian Islands and of other island floras in the Pacific region. Phylogenetic systematics and evolution of vascular plants, especially lycophytes and ferns; evolutionary and ecological genetics of plant populations; conservation biology; historical biogeography.

Link to my Flickr site with photos of plants (mostly):

Link to an online taxonomic key to the Ferns of the Hawaiian Islands

Spreadsheet of Hawaiian Fern and Lycophyte names updated to follow PPG I (2016).

Errata for book Ranker & Haufler 2008 – Biology and Evolution of Ferns and Lycophytes.

Consortium of Pacific Herbaria website


    • 2014–2017: President-Elect, President, Past President, American Society of Plant Taxonomists
    • 2013–2016: President-Elect, President, Past President, Botanical Society of America
    • 2008:   Plant Species Biology Best Paper Award (see Ramp, Ranker, & Collinge, 2008, in CV)
    • 2007:   Elected Fellow of the American Association for the Advancement of Science (AAAS) “For significant contributions to the fields of phylogeny and evolution of vascular plants, particularly to the biogeography of island floras in the Pacific”
    • 2002–2006: President-Elect, President, American Fern Society
    • 1997:   Award for Excellence and Dedication in Teaching, Mortar Board Senior Honor Society, University of Colorado at Boulder
    • 1992:   Edgar T. Wherry Award for the Best Contributed Paper presented to the Pteridological Section of the Botanical Society of America at the annual meeting (see Ranker, Floyd, & Trapp, 1993, in CV)
  • 1981:   Recipient of Outstanding Graduate Student Award, Department of Biology, Humboldt State University

Ranker Lab Alumni

University of Colorado, Department of Ecology and Evolutionary Biology

  • Anna M. Arft, Ph.D. 1995. Genetics, demography, and conservation management of the rare orchid Spiranthes diluvialis (Orchidaceae). Current job: Teacher, San Diego Natural History Museum, San Diego, California.
  • Sandra K. Floyd, M.A. 1995. Population structure, dynamics, and genetics of Gaura neomexicana ssp. coloradensis (Onagraceae), a rare semelparous perennial. Current job: Research Associate, Monash University, Melbourne, Australia.
  • Chrissen E. C. Gemmill, Ph.D. 1996. Population genetics and systematics of the Hawaiian taxa Pritchardia (Arecaceae) and Brighamia (Campanulaceae). Current job: Senior Lecturer, University of Waikato, Hamilton, New Zealand.
  • Robin A. Bingham, Ph.D. 1997. Reproductive biology and genetic structure in foothill and alpine populations of Campanula rotundifolia L. (Campanulaceae). Current job: Professor, Western State College, Gunnison, Colorado.
  • Kendra A. Mingo, M.A. 1997. Phylogenetic systematics and conservation genetics of the Sesbania tomentosa complex (Fabaceae) in Hawaii. Current job: Assistant Director, Office of Faculty Research and Resources, Willamette University, Salem, Oregon.
  • Carla A. Wise, Ph.D. 1997. The importance of genetic factors in the persistence of plant populations: Modeling problems in conservation biology with Brassica rapa. (Co–advisor with Yan Linhart) Current job: Environmental Writer, Corvallis, Oregon.
  • Jennifer M. O. Geiger, Ph.D. 2003. Origin and diversification of Hawaiian Dryopteris (Dryopteridaceae). Current job: Associate Professor & Department Chair, Carroll College, Helena, Montana.
  • Laura Mujica-Crapanzano, Ph.D. 2004. Landscape analysis of vegetation and diversity patterns across the forest–tundra ecotone of Niwot Ridge, Colorado. (Co–advisor with Patrick Bourgeron). Current job: Instructor, University of Hawai‘i, Maui College.
  • Jennifer M. Ramp Neale, Ph.D. 2005. Microevolutionary dynamics and population genetics of the endangered California vernal pool sunflower Lasthenia conjugens (Asteraceae). (Co–advisor with Sharon Collinge). Current job: Director of Research and Conservation, Denver Botanic Gardens, Denver, Colorado.
  • Shannon D. Fehlberg, Ph.D. 2006. Evolutionary diversification of Encelia (Asteraceae) in the Sonoran, Mohave, and Peninsular deserts. Current job: Conservation Biologist, Desert Botanical Garden, Phoenix, Arizona.
  • Jonathan Krieger, Ph.D. 2007. The evolution of developmental modules and lability of leaf form in the fern genus Pleopeltis (Polypodiaceae). (Co–advisor with Robert Guralnick) Current job: Global Plants Initiative Coordinator, Royal Botanic Gardens, Kew.
  • Sarada Krishnan, Ph.D. 2011.Population Genetic Variation and Gene Flow Studies in Threatened Coffea species in Madagascar: Implications for Conservation Management and Development of a Sustainable, Genetically Diverse Agroforestry System. Current job: Director of Horticulture, Denver Botanic Gardens, Denver, Colorado.
  • Melissa Islam, Ph.D. 2011. Phylogenetic systematics and historical biogeography of Erythroxylum (Erythroxylaceae). Current job: Associate Director of Research and Head Curator of the Herbaria, Denver Botanic Gardens, Denver, Colorado.
  • Margaret Wright, M.A. 2007. A genetic comparison of bog vs. forest populations of Metrosideros polymorpha (Myrtaceae) in Hawai‘i. Current job: Mom, Tempe, Arizona.

University of Colorado, Museum and Field Studies Graduate Program

  • Jan I. Bernstein, M.S. 1994. Open Storage: A Survey. Current job: NAGPRA Consultant, Denver, Colorado.
  • Dina A. Clark, M.S. 1995. Floristic survey of the Mesa de Maya region of southeastern Colorado. Current job: Collections Manager, University of Colorado Museum of Natural History, Boulder, Colorado.
  • Mark Duff, M.S. 1994. Population genetics of the Channel Island endemic Lyonothamnus floribundus (Rosaceae). Last known job: Biology Instructor at Weber State University, Ogden, Utah.
  • Julie E. Korb, M.S. 1997. Vegetation dynamics in four ecosystems along an elevational gradient in the Front Range, Colorado. Current job: Associate Professor, Ft. Lewis College, Durango, Colorado.
  • Andrea Orthner, M.S. 1999. Flora of the Buffalo Peaks Wilderness Area and vicinity, Mosquito Range, Colorado. Current job: Field Botanist, Western Ecological Resource, Inc., Boulder, Colorado.
  • Erin (Schaaf) Robertson, M.S. 2000. Limits to female reproductive success in the bottle gentian Pneumonanthe bigelovii (Gentianaceae). Recent job: Staff Biologist, Center for Native Ecosystems, Denver, Colorado. Current job: Mom, Boulder, Colorado.
  • Monique McHenry, M.S. 2005. Ferns and lycophytes of the Southern Rocky Mountain Region. Current jobs: Executive Director, Vermont Patients Alliance Inc., Montpelier, Vermont and Assistant Professor, University of Vermont, Burlington, Vermont.
  • Pamela Regensberg, M.S. 2007. Flora of Baca National Wildlife Refuge. Current job: Herbarium Collections Assistant, Denver Botanic Gardens, Denver, Colorado.
  • Bethany Lewis, M.S. 2008. Floristic Survey of the Arapaho National Wildlife Refuge Complex of North Park, Colorado, and Laramie Plains, Wyoming. Current job: Field Biologist, Bureau of Land Management, Pinedale, Wyoming.

University of Hawai‘i at Mānoa, Department of Botany

  • Amanda L. Vernon, M.S. 2011. A Web–based Interactive Identification Key to the Hawaiian Ferns. Current job: Curatorial Assistant, National Tropical Botanical Garden, Kauai. Current job: Consulting Botanist, Boston, Massachusetts.
  • Tiffany Thair, M.S. 2011. Soil seed bank dynamics in a remnant lowland Hawaiian dry forests: implications for restoration. Current job: Project Manager, SWCA Environmental Consultants, Honolulu, Hawai‘i.
  • Marian Chau, Ph.D. 2012. Conservation of the endangered Hawaiian fern ‘ihi‘ihilauākea (Marsilea villosa): A synthesis of experimental restoration, community ecology, and population genetics. Current job: Director, Seed Conservation Laboratory-Hawaiian Rare Plant Program, Harold L. Lyon Arboretum, University of Hawai‘i at Mānoa.
  • Autumn A. Amici, M.S. 2013. Impacts of logging on primary forests of Siboma Village in the Morobe Province, Papua New Guinea. Current position: Doctoral student, University of Utah.
  • Patricia Sendão, M.S. 2019. Assessing the viability of ex situ fern spore collections at Lyon Arboretum Seed Conservation Laboratory, Hawaiian Rare Plant Program, University of Hawai‘i. Current position: Student in Environmental Law, University of Hawai‘i.

Selected Publications

  • Sundue, M. A., B. S. Parris, T. A. Ranker, A. R. Smith, E. L. Fujimoto, D. Zamora-Crosby, C. W. Morden, W.-L. Chiou, C.-W. Chen, G. Rouhan, R. Y. Hirai, and J. Prado. 2014. Global phylogeny and biogeography of grammitid ferns (Polypodiaceae). Molecular Phylogenetics and Evolution 81: 195–206.
  • Ranker, T. A. and M. A. Sundue. 2015. Why are there so few species of ferns? Trends in Plant Science 20: 402–403.
  • Sundue, M. A., S. P. Sylvester, M. Kessler, B. Lyons, T. A. Ranker, and C. W. Morden. 2015. A new species of Moranopteris (Polypodiaceae) from inaccessible ledges in the high Andes of Peru. Systematic Botany 40: 652–657.
  • Sundue, M. A., W. L. Testo, and T. A. Ranker. 2015. Morphological innovation, ecological opportunity, and the radiation of a major vascular epiphyte lineage. Evolution 69: 2482–2495.
  • Ranker, T. A. 2016. What do we know about Hawaiian ferns and lycophytes? Journal of Systematics and Evolution 54: 626–637.
  • The Pteridophyte Phylogeny Group. 2016. A community-derived classification for extant lycophytes and ferns. Journal of Systematics and Evolution 54: 563–603. (T. A. Ranker, one of 94 contributors)
  • Bauret, L., M. Gaudeul, M. A. Sundue, B. S. Parris, T. A. Ranker, F. Rakotondrainibe, S. Hennequin, J. Ranaivo, M.-A. Selosse, and G. Rouhan. 2017. Madagascar sheds new light on the molecular systematics and biogeography of grammitid ferns: new unexpected lineages and numerous long-distance dispersal events. Molecular Phylogenetics and Evolution 111: 1–17.
  • Kuo, L.-Y., A. Ebihara, M. Kato, G. Rouhan, T. A. Ranker, C.-N. Wang, and W.-L. Chiou. 2018. Morphological characterization of infra-generic lineages in Deparia (Athyriaceae; Polypodiales). Cladistics 34: 78–92.
  • Ranker, T. A., C. T. Imada, K. Lynch, D. D. Palmer, A. L. Vernon, and M. K. Thomas. 2019. Taxonomic and Nomenclatural Updates to the Fern and Lycophyte Flora of the Hawaiian Islands. American Fern Journal. 109: 54–72.