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University of Central Oklahoma

Education and Certifications

  • B.S. Valley City State University
  • M.S. University of Idaho
  • Ph.D. University of Toronto


  • Biology Faculty, University of Central Oklahoma, 1988-present
  • Adjunct Instructor, Rose State College, Spring semesters 1994, 1996, 1998
  • Visiting Assistant Professor, University of Oklahoma Biological Station, summers 1989, 1993
  • Postdoctoral Scholar, Tulane University, 1985-88
  • Visiting Assistant Professor, Western Washington University, Fall quarter, 1984
  • Internship, Boston University Space Biology Program, served at Earth Resources Laboratory, NASA, John Stennis Space Center, MS, summer 1983
  • High school science and math teacher, Fergus Falls, MN, 1974; Courtenay, ND, 1976-77

Classes Taught

  • Introductory Microbiology
  • Microbiology for Majors
  • Plant Biology
  • General Biology
  • Plant Kingdom
  • Mycology
  • Biological and Medical Terminology
  • Tropical Biology

Research, Published Work, and Scholarly Activities

Research Interests 

Research is important and rewarding part of Clark's academic life. His interest is in the taxonomy and ecology of the higher fleshy fungi, mainly the mushroom-type fungi. His dissertation research was on the genus Tricholoma of the Great Lakes Region. He continues his work on the genus in both tropical and temperate regions and has incorporated DNA sequencing as part of his research approach. Other projects include the documentation of the mushroom-type fungi that occur in Oklahoma, southeast Texas and the Gulf Coast region. His first experience in the tropics took place in the Venezuelan llanos. Although the llanos is a wet environment, fungi were abundant in the gallery forests and other elevated areas that did not flood. He continued his tropical work in the lowland rain forests of Costa Rica where he has collected extensively at La Selva Biological Station and also collected on Barro Colorado Island, Panama. He has also collected in the Atlantic Forest region of NE Brazil, oak forests of Colombia and Costa Rica, the oak and pine forests of Belize and Mexico, and the pre-montane forests of western Panama.  Along with other UCO faculty he is documenting the diversity of arthropod inhabitants on fleshy fungi of Oklahoma.  


Lewis, D.P., J.F. Ammirati, K. Liimatainen, T. Niskanen, C. L. Ovrebo, M.E. Smith, J. Justice, L. Kaminsky. 2023. Cortinarius watsoneae, a new species of Agaricomycetes (Cortinariaceae) from the Gulf States. J. Bot. Res. Inst. Texas (17(1): 259-264.

Liimatainen, K, J.F. Ammirati, T. Niskanen, A. Corrales, C. Ovrebo, B. Dima, R. Halling, D. Savage. Nomenclatural novelties. 2022.  Index Fungorum no. 528.  p. 1-10.

Matheny, B.P., A. Corrales, M.G. Graddy, R.E. Halling, J. Kalichman, L. V. Kudzma, C.L. Ovrebo, R.A. Swenie, N.C. Walker. 2022. A revision of the Inocybe grammata group in North America including four new taxa.  Brittonia. Published online, 7 Sept. 2022.  ,

Cabral, T.S., G.C.S. Melanda, N. Mendonça de Assis, C. Ovrebo, I.G. Gaseia, M.P. Martin. 2022.  Loosening the belt: unknown diversity of the strangled stinkhorn genus Staheliomyces (Phallales, Basidiomycota). Mycol. Progr. 21 (4), 46. 17 p. Published online, 11 April 2022.

Ovrebo, C.L., R.E.Halling, K.W. Hughes, M. Kuo. 2021. New species and records of Tricholoma (Agaricales: Tricholomataceae) sections Genuina and Megatricholoma from Costa Rica and United States. J. Bot. Res. Inst. Texas 15(2): 545-557.

Manz, C., S. Adamčík, B.P. Looney, A. Corrales, C. Ovrebo, K. Adamčíková, T. Hofmann, F. Hampe, M. Piepenbring. 2021. Four new species of Russula subsection Roseinae from tropical montane forests in western Panama. PloS ONE 16(10):e0257616. Oct 13.

Vera, M., S. Adamčík, K. Adamčíková, F. Hampe, M. Caboň, C. Manz, C. Ovrebo, M. Piepenbring, and A. Corrales.  2021. Morphological and genetic diversification of Russula‌ floriformis, sp. nov., along the Isthmus of Panama. Mycologia 113(4): 807-827. DOI: 10.1080/00275514.2021.1897377

Corrales, A., and C.L. Ovrebo. 2021. Fungi of the Fortuna Forest Reserve: Taxonomy and ecology with emphasis on ectomycorrhizal communities. In: J.S. Dalling & B.L. Turner, eds. Fortuna Forest Reserve, Panama, Interacting effects of climate and soils on the biota of a wet premontane tropical forest.  Washington, D.C.: Smithsonian Scholarly Press 112. p. 137-153. 

Ammirati, J.F., R.E. Halling, A. Corrales, C.L. Ovrebo, T. Niskanen, K. Liimatainen, S. Garnica.  2021. Nomenclatural Novelties. Index Fungorum no. 474. 4 p. 

Ovrebo, C. L., and Jay Justice. 2020. Some common Amanita species of Oklahoma. Okla. Nat. Pl. Rec. 20: 58-67.

Lewis, D.P, C.L. Ovrebo, N.J. Justice. 2020. Literature update for Texas fleshy Basidiomycota with new vouchered records for southeast Texas. J. Bot. Res. Inst. Texas 14(2):465-479.

Freitas-Neto, J.F., Sousa, J.F., Ovrebo, C.L., Martin, M.P., Baseia, I.G. 2020.  Geastrum calycicoriaceum Freitas-Neto, J.O. Sousa, Ovrebo, M.P. Martin & Baseia sp. nov. Fungal Planet description sheets: Persoonia 44, 2020: 392-393, sheet 1080.

Corrales, A., A.W. Wilson, G.M. Mueller, C. Ovrebo. 2020. Novel Laccaria species from Juglandaceae forest in Panama with notes on their ecology. Frontiers of Microbiology, published online, 17 July. Doi:10:3389/micb.2020.01597

Adamčík, S., B. Looney, M. Caboň, S. Jančovičová,  K. Adamčíková, P. G. Avis, M. Barajas, R. P. Bhatt, A. Corrales, K. Das, F. Hampe, A. Ghosh, G. Gates, V. Kälviäinen, A. N. Khalid, M. Kiran, R. De Lange, H. Lee, Y. W. Lim, A. Kong, C. Manz, C. Ovrebo, M. Saba, T. Taipale, A. Verbeken, K.  Wisitrassameewong, B. Buyck.  2019.  The quest for a globally comprehensible Russula language.  Fungal Diversity: p. 1-81, published online, 24 October 2019.

Varga, T., K. Krizsán, C. Földi, B. Dima, M. Sánchez-García, S. Sánchez-Ramírez, G.J. Szöllősi, J.G. Szarkándi, V. Papp, L. Albert, W. Andreopoulos, C. Angelini, V. Antonín,  K.W. Barry, N.L. Boughe, P. Buchanan, B. Buyck, V. Bense, P. Catcheside, M. Chovatia, J. Cooper, W. Dämon, D. Desjardin, P. Finy, J. Geml, S. Haridas, K. Hughes, A. Justo, D. Karasiński, I. Kautmanova, B. Kiss, S. Kocsubé, H. Kotiranta, K.M. LaButti, B.E. Lechner, K. Liimatainen, A. Lipzen, Z. Lukács, S. Mihaltcheva, L.N. Morgado, T. Niskanen, M.E. Noordeloos, R.A. Ohm, B. Ortiz-Santana, C. Ovrebo, N. Rácz, R. Riley, A. Savchenko, A. Shiryaev, K. Soop, V. Spirin, C. Szebenyi, M. Tomšovský, R.E. Tulloss, J. Uehling, I.V. Grigoriev, C. Vágvölgyi, T. Papp, F.M. Martin, O. Miettinen, D.S. Hibbett and L.G. Nagy.  2019.  Megaphylogeny resolves global patterns of mushroom evolution.  Nature Ecology & Evolution 3: 668-678. Published online 18 March 2019.  

Freitas-Neto, J.F.,  J.O. Sousa, C.L. Ovrebo, and I.G. Baseia.  2019.  Geastrum echinulatum and G. rusticum(Geastraceae, Basidiomycota) – two new records for Central America. Studies in Fungi 4(1): 7-13. Doi 10.5943/sif/4/1/2

Ovrebo, CL, Hughes, KW, Halling, RE.  2019.  Three new species of Tricholoma from Costa Rica. Phytotaxa 392(1): 33-44.

Góis JS, Cruz RHSF, Ovrebo CL and Baseia IG.  2018. Cyathus tenuicorticalis (Agaricales, Basidiomycota), a new species from La Selva Biological Station, Costa Rica. Studies in Fungi 3(1): 256-263. Doi 10.5943/sif/3/1/26.

Ovrebo, C. L., and K. W. Hughes. 2018. Tricholoma smithii, a new species in the Pardinicutis complex from New Mexico and Colorado. N. Amer. Fungi 13(1):1-9. 

Ovrebo, C. L. and S. Brandon. 2017. First record of Chorioactus geaster from Oklahoma. Okla. Nativ. Pl. Rec. 17: 69-21.

Barbosa-Silva, A. C. L. Ovrebo, B. Ortiz-Santana, M. C. A. Sá, M. A. Sulzbacher, M. Roy & F. Wartchow. 2017. Tylopilus aquarius comb. and stat. nov., and its new variety from Brazil.  Sydowia 69: 115-122.   

Sulzbacher, M. A., F. Wartchow, C. L. Ovrebo, J. O. Sousa, I. G. Baseia, B. Moncada, R. Lücking. 2016. Sulzbacheromyces caatingae: notes on its systematics, morphology and distribution based on ITS barcoding sequences. The Lichenologist 48(1): 61–70.

Mata, Juan L., Clark L. Ovrebo, Timothy J. Baroni, Karen W. Hughes.  2016. New species of neotropical Rhodocollybia.  Mycotaxon 131: 235-245. 

Wartchow, F,  M.A. Sulzbacher, M-A. Selosse, T. Grebenc, M.C. Aime, M.C.A. Sá, F.G.B. Pinheiro, I.G.Baseia, C.L. Ovrebo.  2015.  Sebacina aureomagnifica, a new heterobasidiomycete from the Atlantic Forest of Northeast Brazil. Mycological Progress 14: 109. 

Vellinga, E.C., Vellinga, T.W. Kuyper, J. Ammirati, D.E. Desjardin, R.E. Halling, A. Justo, T. Lassoe, T. Lebel, D.J. Lodge, P.B. Matheny, A.S. Methven, Pierre-Arthur Moreau, G.M. Mueller, M.E. Noordeloos, J.Nuytinck, C.L. Ovrebo, and A. Verbeken. 2015.  Six simple guidelines for introducing new genera of fungi.  IMA Fungus 6: 65-68.

Lodge, D.J., Padamsee,  M.,  Matheny, B., Aime, M.C., Cantrell, S.A., Boertmann, D., Kovalenko  A, Vizzini, A., Dentinger, B.T.M, Kirk, P.M., Ainsworth, A.M., Moncalvo, J-M., Vilgalys, R., Larsson, E., Lücking, R., Griffith, G.W., Smith, M.E., Norvell, L.L., Desjardin, D.E., Redhead, S.A., Ovrebo, C.L., Lickey, E.B., Ercole, E., Hughes, K.W., Courtecuisse, R., Young, A., Binder, M., Minnis, A.M., Lindner, D.L., Ortiz-Santana, B., Haight, J., Læssøe, T.,  Baroni, T. J., Geml, J., Hattori, T.J.  2014.  Molecular phylogeny, morphology, pigment chemistry and ecology in Hygrophoraceae (Agaricales). Fungal Diversity: 64: 1-99..  DOI 10.1007/s13225-013-0259-0.

Ovrebo, C. L., D. J Lodge, & M. C. Aime.  2011.  A new Cantharocybe from Belize with notes on the type of Cantharocybe gruberi.  Mycologia 103: 1102-1109

Mata, J. L., and C. L. Ovrebo.  2009.  New reports and illustrations of Gymnopus for Costa Rica and Panama. Fungal Diversity 38:  125-131.

Lewis, D. P., and C. L. Ovrebo.  2009.  Mycological literature on Texas fleshy Basidiomycota, two new combinations, and new fungal records for Texas.   J. Bot. Res. Inst. Texas 3(1): 257-271. 

Lodge, D.J., and C. L. Ovrebo.  2008.  First records of Hygrophoraceae from Panama including anew species of Camarophyllus and a new veiled species in Hygrocybesection Firmae. Fungal Diversity 32: 69-80.

Guzmán-Dávalos, L., M. Contu, A. Ortega, A.. Vizzini, M. Herrera, C. Ovrebo, A. Rodríguez, R. Villalobos-Arámbula, V. Palomera, G. Vargas, A. Santerre.  2008.  New morphological and molecular data on Gymnopilus purpureosquamulosus an its phylogenetic relationships among similar species.  Sydowia 60: 41-56.

Ovrebo, C. L., and N. S. Weber.  2008.  Common spring mushrooms of Oklahoma.  Okla. Nativ. Pl. Rec. 8(1): 57-60. 

Ovrebo, C. L., and T. J. Baroni.   2007.  New taxa of Tricholomataceae and Entolomataceae (Agaricales) from Central America.  Fungal Diversity 27(1): 157-170.

Ovrebo, C. L.  2006.  Cedar-apple rust.  Okla Nativ. Pl. Rec 6: 80-81. 

Desjardin, D., and C. L. Ovrebo.  2006.  New species and new records of Marasmius from Panama.   Fungal Diversity 21: 19-39.

Akers, B. P., and C. L. Ovrebo. 2005.  Leucoagaricus bivelatus, a new volvate lepiotoid species.  Mycotaxon 91: 303-308.

Ovrebo, C. L.  2004.  Common lawn and garden fungi of Central Oklahoma.  Okla. Nativ. Pl. Rec: 4(1): 48-54.

Buyck, B, and C. L. Ovrebo.  2002.  Some interesting Russula species from Panama.  Mycologia 94(5): 888-901.

Guzmán-Dávalos, L., and C. L. Ovrebo.  2001.  Some species of Gymnopilus from Costa Rica and Panama.  Mycologia 93(2): 398-404.

Guzmán, G., and C. L. Ovrebo.  2000.  New observations on sclerodermataceous fungi.  Mycologia 92(1):  174-179.

Maas Geesteranus, R. A., and C. L. Ovrebo. 1997.  A new species and new section of Mycena from Costa Rica.  Persoonia 16(3): 393-395.

Wu, Q., G. M. Mueller, and C. L. Ovrebo.  1997.  An index to genera, species, and infraspecific taxa of basidiomycete fungi described by Rolf Singer.   Fieldiana, new series no. 38, publ. 1482: 13-99. 

Ovrebo, C. L.  1996.  The agaric flora (Agaricales) of La Selva Biological Station, Costa Rica.   Rev. Biol. Trop. 44 (Suppl. 44): 39-57.  (Publ. 1997)

Tulloss, R. E., C. L. Ovrebo, and R. E. Halling.  1992. Studies on Amanita (Amanitaceae) from Andean Colombia.  Memoirs of the New York Botanical Garden 66: 1-46.

Miller, Jr., O. K., C. L. Ovrebo, and W. R. Burk.  1991.  Neolysurus: a new genus in the Clathraceae from Costa Rica. Mycol. Res.: 95(10): 1230-1234.

Ovrebo, C. L.  1990.  An introduction to the infrageneric classification of Tricholoma.  McIlvainea 9(2): 61-64.

Singer, R., C. L. Ovrebo, & D. P. Lewis.  1990.  A new species of Melanomphalia (Crepidotaceae).  Mycotaxon 37: 47-52.      

Singer, R., C. L. Ovrebo, &   R. E. Halling.  1990.  New species of Phylloporus and Tricholomopsis from Colombia with notes on Phylloporus boletinoides.  Mycologia 82(4): 452-459.

Ovrebo, C. L.  1989.  Tricholoma subgenus Tricholoma sect. Albidogrisea: North American species found principally in the Great Lakes Region.  Can. J. Bot. 67: 3134-52.

Alexander, J., A. L. Welden, and C. L. Ovrebo.  1989.  Trichaptum sector (Ehrenb.: Fr.) Kreisel (Polyporaceae s.l.).  Mycol.   Helv. 3(3): 291-302.

Welden, A. L., and C. L. Ovrebo.  1989.  Notes on tropical and warm temperate Basidiomycetes.  Mycotaxon 34(2): 601-614.

Alexander, J., A. L. Welden, and C. L. Ovrebo.  1989.  Trichaptum sector (Ehrenb.: Fr.) Kreisel (Polyporaceae s.l.).  Mycol.   Helv. 3(3): 291-302.

Ovrebo, C. L., and T. J. Baroni.  1988.  Three new species of Rhodocybe from Costa Rica.  Mycologia 80(4): 508-514.

Ovrebo, C. L.  1988.  Notes on the cultural characters, morphology and distribution of Ripartitella brasiliensis.  Mycotaxon 31: 229‑237.

Cibula, W. G., and C. L. Ovrebo.  1988.  Mycosociological studies of mycorrhizal fungi in two lobolly pine plots in Mississippi and some relationships with remote sensing.  Pp. 268-307.  In Remote sensing for resource inventory, planning and monitoring.  Proceedings of the 2nd Forest Service Remote Sensing Application Conference - Slidell, Louisiana and NSTL, Mississippi.  Ed., J. D. Greer.  Am. Soc. Photogram. & Rem. Sens.

Halling, R. E., and C. L. Ovrebo.  1987.  A new species of Rozites from oak forests of Colombia, with notes on biogeography.  Mycologia 79 (5): 674‑678.

Ovrebo, C. L.  l986.  Three new species of Tricholoma with a description of Tricholoma luteomaculosum.  Mycologia 78(3):  418‑425.

Ovrebo, C. L., and R. E. Halling.  l986.  Tricholoma fulvimarginatum (Tricholomataceae): a new species from North  America associated with cottonwood.  Brittonia 38(3):  260‑263.

Ovrebo, C. L., R. E. Halling, & T. J. Baroni.  1984.  A note on Tricholoma niveipes.  Mycotaxon 20(1): 474‑478.

Baroni, T. J., and C. L. Ovrebo.  1983.  Tricholoma manzanitae‑a new species from California.  Mycotaxon 18(2): 299‑302.

Ovrebo, C. L.  1983.  New records of fleshy fungi from Venezuela.  Mycotaxon 18(2): 355‑356.

Harrison, K. A., and C. Ovrebo.  1982.  Further notes on Steccherinum crassiusculum (Hydnaceae).  Contr. Univ.  Mich. Herb. 15: 177‑179.

Ammirati, J. F., and C. L. Ovrebo.  1979.  Type studies: some Cortinarius and Tricholoma species described by Charles Horton Peck.  Mycotaxon 8(2): 353‑371.

Ovrebo, C. L., and A. H. Smith.  1979.  Studies on Tricholoma vaccinum and T. imbricatum in North America. Mich. Bot.18: 99‑106. 

Ovrebo, C. L., and E. E. Tylutki.  1975.  New species and a new combination of Tricholoma (Agaricales) from the Pacific Northwest.  Mycologia 67: 75‑82.

Professional and Community Involvement

Clark is a contact resource for the Oklahoma Poison Control Center for mushroom poisoning cases, also identifies mushrooms for local hospital emergency rooms and has been interviewed by local TV and newspaper media. He identifies mushrooms for local citizens and leads mycology field trips for the Oklahoma Academy of Science and is a frequent fungus identifier for the Oklahoma Bioblitz. He travels to regional and national mushroom forays where he serves as a mushroom identifier and gives talks or workshops. He is the co-scientific advisor for the Gulf States Mycological Society. In addition, he has held committee positions for the Mycological Society of America, North American Mycological Association, Oklahoma Academy of Science, Oklahoma Native Plant Society and UCO Sigma Xi Chapter. He also is a member of Sigma Xi, Kappa Delta Pi and Beta Beta Beta.

Honors and Awards

  • UCO Sigma Xi Club Researcher of the Year
  • Outstanding Researcher Award, College of Mathematics and Science
  • Faculty Merit Award for Research
  • Anne Long Award, Oklahoma Native Plant Society

The views expressed by UCO faculty and staff on their personal websites and social media pages do not necessarily reflect the positions of the University of Central Oklahoma. UCO faculty and staff are advised to follow the university’s social media guidelines and are expected to conduct themselves in accordance with policies outlined in UCO’s Employee Handbook and/or Faculty Handbook.