Jeffery J. Morawetz Ph.D.

Postdoctoral Researcher

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Research Interests

I have broad interests in the systematics, taxonomy, morphology and structure of flowering plants. My primary research focus has been on the fascinating family Orobanchaceae.

The Orobanchaceae (broomrape family) are an economically important cosmopolitan parasitic plant family containing 92 genera and ca. 2100 species. The family is ideal for studying the evolution of parasitism because it contains the full range of trophic abilities: non-parasites, facultative and obligate hemiparasites, and holoparasites (the non-parasitic Lindenbergia is sister to the rest of the family). Transitions from hemi- to holoparasitism have been hypothesized at least five times, but the actual number is likely much higher. Our recent discoveries within the enigmatic tropical genus Harveya, a primarily holoparasitic taxon that includes two hemiparasitic species, support three to eight transitions alone!

My current research at Rancho Santa Ana Botanic Garden is focused on anatomical studies of the haustorium (parasitic organ) in Orobanchaceae. I am interested in characterizing haustorial structure and vascular tissue continuity at the host-parasite interface for each lineage. It is currently unclear whether phloem is present in the haustoria of most genera. From my preliminary work, I have documented greater variation in the number of xylem strands connecting host and parasite than has previously been reported. I am investigating the role and importance of transfer cells and plasmodesmatal connections in haustoria using TEM (transmission electron microscopy).

I am continuing my research on the systematics of tropical Orobanchaceae with my colleague Dr. Christopher Randle at Sam Houston State University in Huntsville. This collaborative effort has been greatly facilitated by receiving an NSF grant to further our research goals! Our fieldwork will take place in Brazil, China, Kenya, Madagascar, and Mexico. Further, we were recently awarded a National Geographic Society grant to expand our studies of tropical Orobanchaceae, focusing on the fascinating diversity of taxa present in Katanga Province, Democratic Republic of the Congo. Many of these Congolese species are heavy metal tolerant (termed “metallophytes”), and some even hyperaccumulate copper and cobalt.

The tropical lineage within Orobanchaceae is economically important because it contains three of the four most noxious parasitic weeds of agriculture found in the family (Aeginetia, Alectra, Striga). Striga alone is responsible for devastating yield losses and crop failures throughout sub-Saharan Africa where subsistence farmers lack resources to effectively battle these tenacious weeds.


Read more

Visit Jeff Morawetz's personal webpage to learn more about his research and read his travel blog.

Read the RSABG news article on Morawetz's research in Oman. Click here to read about the project on the Euphorbia PBI website.

Read about Morawetz's National Geographic Society Grant Nov. 2011


Ph.D. The Ohio State University, Department of Evolution, Ecology and Organismal Biology, 2007
B.S. University of Wisconsin, Madison, Department of Botany, 2000


Recent papers:

Morawetz, J. J. A clearing protocol for haustoria in Orobanchaceae. Applications in Plant Sciences. Submitted.

Dorsey, B. L., T. Haevermans, X. Aubriot, J. J. Morawetz, R. Riina, V. W. Steinmann and P. E. Berry. Phylogenetics, morphological evolution, and classification of Euphorbia subgenus Euphorbia (Euphorbiaceae). Taxon. Submitted.

Berry, P. E., J. A. Peirson, V. W. Steinmann, J. J. Morawetz, R. Riina, Y. Yang, D. Geltman, N. I. Cacho. Euphorbia (Euphorbiaceae). Flora of North America. Submitted.

Yang, Y., R. Riina, J. J. Morawetz, T. Haevermans, X. Aubriot, and P. E. Berry. Molecular phylogenetics and classification of Euphorbia subgenus Chamaesyce (Euphorbiaceae). Taxon. In press.

Horn, J. W., B. W. van Ee, J. J. Morawetz, R. Riina, V. W. Steinmann, P. E. Berry and K. Wurdack. 2012. Phylogenetics and the evolution of major structural characters in the giant genus Euphorbia L. (Euphorbiaceae). Molecular Phylogenetics and Evolution 63: 305-326.

Morawetz, J. J. 2012. Aureolaria (Orobanchaceae). Flora of North America. (published online 8 March 2012)

Morawetz, J. J. 2011. Alectra, Melasma (Orobanchaceae). Flora Mesoamericana. (published online 21 Dec 2011)

Morawetz, J. J. and M. J. M. Christenhusz. 2011. Buchnera (Orobanchaceae). Flora Mesoamericana. (published online 21 Dec 2011)

Morawetz, J. J. and A. D. Wolfe. 2011. Taxonomic revision of the Alectra sessiliflora complex (Orobanchaceae). Systematic Botany 36 (1): 141-152.

Morawetz, J. J. and C. P. Randle. 2010. The status of Harveya alba (Orobanchaceae). Kew Bulletin 65 (3): 495-496.

Morawetz, J. J., C. P. Randle and A. D. Wolfe. 2010. Phylogenetic relationships among the tropical clade of Orobanchaceae. Taxon 59 (2): 416-426.

Download Jeffery Morawetz's CV (PDF) morawetz_cv.pdf