Michael G. Simpson
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      San Diego State University
Department of Biology

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MICHAEL G. SIMPSON, Professor Emeritus

Curator, SDSU Herbarium

Research Gate Profile

Author, Plant Systematics
(See Plant Systematics Resources)

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Email msimpson@sdsu.edu






Mailing Address

Dr. Michael G. Simpson
Department of Biology
San Diego State University
San Diego, CA 92182-4614

B.S.: University of Florida
M.S.: University of North Carolina, Chapel Hill
Ph.D. : Duke University

General Research Interests: 
Plant systematics, plant taxonomy, floristics.

My research in plant systematics lab focuses on the systematics and evolution of land plants with three general objectives:
   1) to infer the phylogenetic relationships of plant groups and to use that pattern of evolutionary history to assess aspects of character evolution, biogeography, ecology, and evolutionary process;
   2) to investigate the delimitation of plant species and infraspecies, especially in evaluating rare/endangered taxa;
   3) to discover the plant species and community structure of regions in floristic studies.

I have interests in American amphitropical disjunct (AAD) plants, those that occur in North and South America, on either side of the neotropics.
See our American Amphitropical Disjunction Working Group:
   Figshare site: https://figshare.com/projects/American_Amphitropical_Disjunctions_AAD_Working_Group/25510
   Figshare data (a compendium of AAD vascular plants): http://dx.doi.org/10.6084/m9.figshare.5479822
   SDSU website listing examples, links, and resources: http://www.sci.sdsu.edu/plants/AAD

My field work in Chile and Argentina was supported in part by the National Geographic Society. I and my colleagues are working on the phylogenetic relationships of the Amsinckiinae (Boraginaceae), many of which have an American amphitropical disjunct plants. See my web page on
Some Plants of Chile/Algunas Plantas de Chile.

Field Botany of San Diego County (co-taught with Dr. Lluvia Flores-Rentería, Scott McMillan, Margie Mulligan, Tom Oberbauer, Dr. Jon Rebman, and Dr. Sula Vanderplank)

: Video clips on SDSU Botany! and the SDSU Herbarium

Plant Systematics Resources
SDSU Herbarium


Simpson, M. G., J. Stephens, and S. Yang. 2020. Noteworthy Collections: Johnstonella angelica (I.M.Johnston) Hasenstab & M.G.Simpson. Madroño 67:5-8. https://doi.org/10.3120/0024-9637-67.1.5

Yost, J. M., K. D. Pearson, J. Alexander, E. Gilbert, L. A. Hains, T. Barry, R. Bencie, P. Bowler, B. Carter, R. E. Crowe, E. Dean, J. Der, A. Fisher, K. Fisher, L. Flores-Renteria, C. M. Guilliams, C. Hatfield, L. Hendrickson, T. Huggins, L. Janeway, C. Lay, A. Litt, S. Markos, S. J. Mazer, D. Mccamish, L. Mcdade, M. Mesler, B. Mishler, M. Nazaire, J. Rebman, L. Rosengreen, P. W. Rundel, D. Potter, A. Sanders, K. C. Seltmann, M. G. Simpson, G. A. Wahlert, K. Waselkov, K. Williams, and P. S. Wilson. 2020. The California Phenology Collections Network: Using digital images to investigate phenological change in a biodiversity hotspot. Madroño 66:130-141. https://doi.org/10.3120/0024-9637-66.4.130

Benet-Pierce, N. and M. G. Simpson. 2019. The taxonomy of Chenopodium hians, C. incognitum, and ten new taxa within the narrow-leaved Chenopodium group in western North America, with special attention to California. Madroño 66:56–75.

Simpson, Michael G.  201
9.  Plant Systematics, 3rd edition.  Elsevier-Academic Press. (web site)

Simpson, M. G., M. E. Mabry, and K. Hasenstab-Lehman. 2019. Transfer of four species of Cryptantha to the genus Johnstonella (Boraginaceae). Phytotaxa 425:279–289. https://doi.org/10.11646/phytotaxa.425.5.3

Mabry, M. E.* and M. G. Simpson. 2018. Evaluating the monophyly and biogeography of Cryptantha (Boraginaceae). Systematic Botany 43: 53-76.
DOI: http://dx.doi.org/10.1600/036364418X696978

Mendoza-Díaz, N., H. Flores-Olvera, M. G. Simpson, and M. J. Moore. 2018. A new and unusual endemic species from the Chihuahuan Desert, Mexico: Antiphytum geoffreyi (Boraginaceae, Echiochiloideae). Phytotaxa 367: 275-283.
: https://doi.org/10.11646/phytotaxa.367.3.7


Aerne-Hains, L.* and M. G. Simpson. 2017
. Vegetative anatomy of the Haemodoraceae and its phylogenetic significance. International Journal of Plant Sciences 178: 117-156. DOI:https://doi.org/10.1086/689199  

Benet-Pierce, N. and M. G. Simpson. 2017. Taxonomic recovery of the species in the Chenopodium neomexicanum complex and description of Chenopodium sonorense sp. nov. Journal of the
Torrey Botanical Society 144: 339-356.

Guilliams, M. C.*, K. Hasenstab-Lehman*, M. Mabry* and M. G. Simpson. 2017. Memoirs of a frequent flier: Phylogenomics reveals 18 long-distance dispersals between North America and South America in the popcorn flowers (Amsinckiinae, Boraginaceae). American Journal of Botany 104: 1717-1728. DOI:https://doi.org/10.3732/ajb.1700369

Simpson, M. G.
, C. M. Guilliams*, K. E. Hasenstab-Lehman*, M. E. Mabry*, and L. Ripma*.
2017. Phylogeny of the popcorn flowers: Use of genome skimming to evaluate monophyly and interrelationships in subtribe Amsinckiinae (Boraginaceae). Taxon 66: 1406–1420.
DOI: https://doi.org/10.12705/666.8

Simpson, M. G., L. A. Johnson and C. M. Guilliams*. 2017. Patterns and processes of American amphitropical disjunctions: New
insights. American Journal of Botany 104: 1597-1599. DOI:https://doi.org/10.3732/ajb.1700433

Simpson, M. G.,
L. A. Johnson, T. Villaverde and C. M. Guilliams*. 2017. American Amphitropical Disjuncts: Perspectives from vascular plant analyses and prospects for future research. American Journal of Botany 104: 1600-1650. DOI: https://doi.org/10.3732/ajb.1700308 (pdf)

Simpson, M. G.
and R. B. Kelley. 2017. Cryptantha nevadensis var. rigida elevated to species with a new name, C. juniperensis. Phytotaxa
295: 227-236. DOI:https://doi.org/10.11646/phytotaxa.295.3.3

Chacón, J., F. Luebert, H. H. Hilger, S. Ovcinnikova, F. Selvi, L. Cecchi, C. M. Guilliams*, K. Hasenstab-Lehman*, K. Sutorý,
M. G. Simpson
, and M. Weigend. 2016. The borage family (Boraginaceae s.str.): A revised infrafamilial classification based on new phylogenetic evidence, with emphasis on the placement of some enigmatic genera. Taxon 65: 523–546. DOI:http://dx.doi.org/10.12705/653.6

Luebert, F., L. Cecchi, M. W. Frohlich, M. Gottschling, C. M. Guilliams*, H. H. Hilger, K. E. Hasenstab-Lehman*, J. S. Miller, M. Mittelbach, M. Nazaire, M. Nepi, D. Nocentini, D. Ober, R. G. Olmstead, F. Selvi, M. G. Simpson, K. Sutorý, B. Valdés, G. K. Walden, and M. Weigend (Boraginales Working Group). 2016. Familial classification of the Boraginales. Taxon 65: 50
2-522. DOI:http://dx.doi.org/10.12705/653.5

Mabry, M. E.*, R. A. Dowdy*, L. M. Simpson, J. P. Rebman, and M. G. Simpson. 2016. Taxonomy of the winged popcorn flower: Cryptantha pterocarya (Boraginaceae). Phytotaxa 253: 97-130. DOI: http://dx.doi.org/10.11646/phytotaxa.253.2.1

McCabe, S. W., M. W. Dodero, and M. G. Simpson. 2016. Dudleya hendrixii: A
new, rare species from Colonet Mesa, Baja California. Madroño 63: 359-365. DOI: https://doi.org/10.3120/0024-9637-63.4.359

Simpson, M. G.
, L. M. Simpson, and J. P. Rebman. 2016. A new, large-flowered variety of Eremocarya micrantha (Boraginaceae). Madroño 63: 39-54. DOI: https://doi.org/10.3120/0024-9637-63.1.39

Benet-Pierce, N. and M. G. Simpson. 2014. The taxonomy of Chenopodium desiccatum and C. nitens, sp. nov. Journal of the Torrey Botanical Society 141: 161-172. DOI: https://doi.org/10.3159/TORREY-D-13-00046.1

Rebman, J. P. and M. G. Simpson. 2014. Checklist of the Vascular Plants of San Diego County, 5th edition. San Diego Natural History Museum Publications.

Ripma, L.*, M. G. Simpson, and K. Hasenstab-Lehman*. 2014. Geneious! Simplified genome skimming methods for phylogenetic systematic studies: A case study in Oreocarya (Boraginaceae). Applications in Plant Sciences
2: 1400062.
DOI: http://dx.doi.org/10.3732/apps.1400062

Simpson, Michael G. 2014. Review of Intermountain Flora: Vascular Plants of the Intermountain West, U.S.A. Subclass Magnoliidae– Caryophyllidae, Vol. 2A. By N. H. Holmgren, P. K. Holmgren, J. L. Reveal, and collaborators. 2012. The New York Botanical Garden Press, Bronx, New York. 742 pp. ISBN 978-0-89327- 520-4, Price $150.00, hardcover.  Madroño 61: 146-147.

Simpson, M. G., K. Hasenstab-Lehman*, and R. B. Kelley. 2014. Typification of the name Johnstonella (Boraginaceae). Taxon 63: 930-931. DOI: http://dx.doi.org/10.12705/634.8

Simpson, M. G.
, R. Dowdy*, J. P. Rebman, R. B. Kelley, and L. M. Simpson. 2014. The recognition of two species in Eremocarya (Boraginaceae): Evidence from fornix bodies, nutlets, corolla size, and biogeography. Madroño 61: 259–275.
DOI: https://doi.org/10.3120/0024-9637-61.3.259


Guilliams, C. M.*, B. A. Veno, M. G. Simpson, and R. B. Kelley. 2013. Pectocarya anisocarpa, a new species of Boraginaceae, and a revised key for the genus in western North America. Aliso 31: 1-13. DOI: http://dx.doi.org/10.5642/aliso.20133101.02

Silveira, M.* and Simpson, M. G. 2013. Phylogenetic systematics of the mesa mints: Pogogyne (Lamiaceae). Systematic Botany 38: 782-794. DOI: https://doi.org/10.1600/036364413X670313

Simpson, M. G.
, J. P. Rebman, K. E. Hasenstab-Lehman*, C. M. Guilliams*, and P. McConnell. 2013. Cryptantha wigginsii (Boraginaceae): A presumed extinct species rediscovered. Madroño 60(1): 24-34. DOI: https://doi.org/10.3120/0024-9637-60.1.24

Simpson, M. G. and J. P. Rebman. 2013. A new species of Cryptantha (Boraginaceae) from the Sierra de San Pedro Mártir, Baja California, Mexico. Madroño 60(1): 35-45. (pdf) Yost, J. M., M. Bontrager, S. McCabe, D. Burton*, M. G. Simpson, K. M. Kay, and M. Ritter. 2013. Phylogenetic relationships and evolution in Dudleya (Crassulaceae). Systematic Botany 38: 1096-1104. DOI: https://doi.org/10.3120/0024-9637-60.1.35

Yost, J. M., M. Bontrager, S. W. McCabe, D. Burton*, M. G. Simpson, K. M. Kay and M. Ritter. 2013. Phylogenetic relationships and evolution in Dudleya (Crassulaceae). Systematic Botany 38: 1096-1104. DOI: https://doi.org/10.1600/036364413X674760


Dodero, M. W.* and M. G. Simpson. 2012. Dudleya crassifolia (Crassulaceae), a new species from northern Baja California, Mexico. Madroño 59: 223-229.

Hasenstab-Lehman, Kristen E.* and M. G. Simpson. 2012. Cat’s Eyes and Popcorn Flowers: Phylogenetic Systematics of the Genus Cryptantha s.l. (Boraginaceae). Systematic Botany 37: 738–757.  NOTE: Winner of the 2014 Grady Webster Award, given by the American Society of Plant Taxonomists, for best publication during the two year period 2012-2013!

Kelley, R. B., M. G. Simpson, and K. E. Hasenstab. 2012. Cryptantha. Pp. 455-468 in B. G. Baldwin, D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken (eds.), The Jepson Manual: Vascular Plants of California. Second Edition. University of California Press, Berkeley, Los Angeles, London.

Silveira, M., M. G. Simpson, and J. D. Jokerst. 2012. Pogogyne. Pp. 850-851 in B. G. Baldwin, D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken (eds.), The Jepson Manual: Vascular Plants of California. Second Edition. University of California Press, Berkeley, Los Angeles, London.

Benet-Pierce, N. and M. G. Simpson. 2010. Chenopodium littoreum (Chenopodiaceae),  a new goosefoot from dunes of south-central coastal California. Madroño 57: 64-72.

Guilliams, C. M.*, Simpson, M. G., and J. P. Rebman. 2011. Calyptridium parryi var. martirense (Montiaceae), a new taxon endemic to the Sierra San Pedro Mártir, Baja California, Mexico. Madroño 58(4): 258-266.

Simpson, M. G., C. M. Guilliams*, and M. Silveira*. 2010. Taxonomy of Calyptridium parryi (Montiaceae). Madroño 57: 145-160.

Simpson, Michael G.  2010.  Plant Systematics, 2nd edition.  Elsevier-Academic Press. (web site)

Pierce, Nuri and Michael G. Simpson. 2009. Polyaperturate pollen types and ratios of heteromorphism in the monocot genus Conostylis R. Br. (Haemodoraceae). Australian Systematic Botany 22: 16-30.

Simpson, Michael G.
and Kristen E. Hasenstab*. 2009. Cryptantha of Southern California. Crossosoma 35: 1-59.

Winner, Annette and Michael G. Simpson.  2007.  A new subspecies of Pentagramma triangularis (Pteridaceae).  Madroño 54(4): 345-353


Rebman, Jon P. and Michael G. Simpson.  2006.  Checklist of the Vascular Plants of San Diego County.  4th edition.  San Diego Natural History Museum, San Diego, California. 

Simpson, Michael G.
2006. Plant Systematics. Elsevier-Academic Press. (web site) NOTE: Winner of the Gleason Award, New York Botanical Garden, 2006

Simpson, Michael G.
and Darren H. Burton*.  2006.  Floral anatomy of the Pontederiaceae and its systematic significance.  Aliso 22: 499-519. In: Columbus, J. T., E. A. Friar, J. M. Porter, L. M. Prince, and M. G. Simpson [eds.].  Monocots:  Comparative biology and evolution.  2 vols.  Rancho Santa Ana Botanic Garden, Claremont, California, U. S. A.

Hargrove, Lori and Michael G. Simpson.  2003. Ultrastructure of heterocolpate pollen in Cryptantha (Boraginaceae).  International Journal of Plant Sciences 164(1): 137-151.

Evans, Timothy M., Robert B. Faden, Michael G. Simpson, and Kenneth J. Sytsma.  2000.  Phylogenetic relationships in the Commelinaceae: I. A cladistic analysis of morphological data.  Systematic Botany 25: 668-691.

Marsden, Kim L.* and Michael G. Simpson.  1999.  Eryngium pendletonensis (Apiaceae), a new species from southern california.  Madroño 46(1): 55-58.

Simpson, Michael G.
  1998.  Reversal in ovary position from inferior to superior in the Haemodoraceae: evidence from floral ontogeny.  International Journal of Plant Sciences 159(3): 466-479

Simpson, Michael G.  1998.  HaemodoraceaeIn: Kubitski, ed. Families and Genera of Flowering Plants.   Volume IV. Flowering Plants Monocotyledons. Alismatanae and Commelinanae (except Gramineae). Pp. 212-222. Springer, Berlin. 

Simpson, Michael G. and Rudall, P.  1998.  TecophilaeaceaeIn: Kubitski, ed. Families and Genera of Flowering Plants.   Volume III. Flowering Plants Monocotyledons. Lilianae (except Orchidaceae). Pp. 429-436. Springer, Berlin. 

Simpson, Michael G.
  and Levin, G. A.  1994.  Pollen ultrastructure of the biovulate Euphorbiaceae.  International Journal of Plant Sciences 155: 313-341

Levin, Geoffrey A., and Michael G. Simpson.  1994.  Phylogenetic implications of pollen ultrastructure in the Oldfieldioideae (Euphorbiaceae).  Annals of the Missouri Botanical Garden 81: 203-238

Levin, Geoffrey A., and Michael G. Simpson.  1994.  Phylogenetic relationships of Hymenocardia and Didymocistus (Euphorbiaceae).  Annals of the Missouri Botanical Garden 81: 239-244

Simpson, Michael G.
  1993.  Septal nectary anatomy and phylogeny in the Haemodoraceae.  Systematic Botany 18: 593-613.

Simpson, Michael G.
  1990.  Phylogeny and classification of the Haemodoraceae.  Annals of the Missouri Botanical Garden 77: 722-784.

Simpson, Michael G.
  1989.  Pollen wall development of Xiphidium coeruleum (Haemodoraceae) and its systematic implications.  Annals of Botany 64: 257-269. (pdf)

Simpson, Michael G.
  1988.  A critique of "Bromeliales, related monocots, and resolution of relationships among Bromeliaceae subfamilies."  Systematic Botany 13: 610-614

Simpson, Michael G.
  1988.  Embryological development of Lachnanthes caroliniana (Haemodoraceae). 
American journal of Botany 75: 1394-1408

Simpson, Michael G.
  1987.  Pollen ultrastructure of the Pontederiaceae:  evidence for exine homology with the Haemodoraceae.  Grana 26: 113-126.

Simpson, Michael G. 
1985.  Pollen ultrastructure of the Tecophilaeaceae.  Grana 24: 77-92.

Simpson, Michael G. 
1985.  Pollen ultrastructure of the Philydraceae.  Grana 24: 23-31.

Simpson, Michael G. 
1983.  Pollen ultrastructure of the Haemodoraceae and its taxonomic significance.  Grana 22: 79-103.

Simpson, Michael G.
and W. C. Dickison.  1981.  Comparative anatomy of Lachnanthes and Lophiola (Haemodoraceae).  Flora 171: 95-113.

Non-referred publications

Simpson, Michael G., E. Gergus, and S. C. McMillan.  20
14Laboratory Manual for Organismal Biology: an Evolutionary Approach. 10th edition.  Rhynchops Press, California.

Simpson, Michael G.
  2013.  Plant Collecting and Documentation Field Notebook
4th edition. Rhynchops Press, California.

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