US National Arboretum

 


Floral and Nursery Plants Research Unit

Dr. Alan T. Whittemore

Research Plant Taxonomist
{Washington, DC}

Alan.Whittemore@ars.usda.gov

PROJECT PLAN TITLE:  
Taxonomy And Genetic Diversity Assessment Of Landscape Trees And Shrubs

INTRODUCTION:  
The primary goals for this project are to assess systematic relationships and the amount and apportionment of genetic diversity within and between species.  The work focuses on the North American elms, hackberries, and oaks (taxa of Ulmus, Celtis, and Quercus), developing genetic marker systems that will facilitate this work and at the same time be useful for breeding and selection work in these genera.  The project also manages and develops the National Arboretum herbarium, the only large herbarium in USDA, focused on cultivated/domesticated plants; collaborates in the documentation of emerging invasive woody plants, and the investigation of traits contributing to their invasiveness; and works to determine the valid botanical and cultivar names for landscape trees and shrubs, and to ensure that those names are properly and consistently applied.

PROGRESS:  
Demonstrated that Ulmus americana, an important nursery crop, consists of two genetic races, diploid and tetraploid, and investigated the reproduction of a triploid hybrid between them.  Demonstrated that hybrids between species of Celtis are much rarer in nature, and harder to synthesize, than previously reported.  Demonstrated that many natural populations of Celtis are apomictic.  Added several thousand specimens a year to the herbarium, including collections documenting important breeding and cultivar collections from many parts of the country.  Carried out other research projects of limited scope relating to other families and genera, including contributions necessary to ensure stable, accurate nomenclature for cultivated plants and their wild relatives and contributions to collaborative projects to produce taxonomic manuals for various areas of North America.

PLANS:   
Determine the genetic relationship between the two genetic races of American elm (Ulmus americana).  Continue to investigate the distribution of apomixis in Celtis, and complete studies of relationships among the species using morphological and DNA markers.  Complete investigations on distribution of genetic markers in selected oaks.  Continue herbarium documention of important breeding and cultivar collections.  Make the general specimen database for the herbarium available on the Web.  Continue to participate in important collaborative taxonomic projects.

RECENT PUBLICATIONS:

2003.  A. T. Whittemore.  Noteworthy collections (District of Columbia).  Castanea 68: 261.

2003.  A. T. Whittemore and A. E. Schuyler.  Scirpus.  Flora of North America  23: 8-21.

2003.  A. A. Reznicek., J. E. Fairey III and A. T. Whittemore.  Scleria.  Flora of North America  23: 242-251.

2004.  Fu Liguo, Xin Yiqun, and A. T. Whittemore.  Ulmaceae.  Flora of China, volume 5: 1-19.

2004  A. T. Whittemore.  Sawtooth oak (Quercus acutissima, Fagaceae) in North America.  Sida 21: 447-454.

2005.  A. T. Whittemore. Genetic structure, lack of introgression, and taxonomic status in the Celtis laevigata - C. reticulata complex (Cannabaceae).  Systematic Botany 30: 809-817.

2005.  A. T. Whittemore.  Validation of the Name Ilex Xaquipernyi J. B. Gable (Aquifoliaceae).  Novon 15: 493-494.

2005  A. T. Whittemore and K. C. Nixon.  Proposal to reject the name Quercus prinus L. (Fagaceae).  Taxon 54: 213-214.

2006.  A. T. Whittemore.  Notes on Southwestern Moraceae.  Sida: Contributions to Botany 22: 769-775.

2006.  A. T. Whittemore.  Berberidaceae.  Pp. 602-607 in G. Yatskievych (ed.), Flora of Missouri, volume 2.

2006.  A. T. Whittemore.  Betulaceae.  Pp. 607-614 in G. Yatskievych (ed.), Flora of Missouri, volume 2.

2006.  A. T. Whittemore.  Caprifoliaceae.  Pp. 765-794 in G. Yatskievych (ed.), Flora of Missouri, volume 2.

2007.  A. T. Whittemore and A. H. Townsend.  Hybridization and Self-Compatibility in Celtis: AFLP Analysis of Controlled Crosses.  Journal of the American Society of Horticultural Science 132: 368-373.

2008.  A. T. Whittemore.  Exotic species of Celtis (Cannabaceae) in the flora of North America.  Journal of the Botanical Research Institute of Texas 2: 627-632.

2008.  A. T. Whittemore.  Proposal to reject the name Ulmus campestris (Ulmaceae) Taxon 57: 656-657.

2009.  A. T. Whittemore.  What is Ranunculus gelidusJournal of the Botanical Research Institute of Texas 3: 245-250.

2009.  R. Olsen and A. T. Whittemore.  Validation of the hybrid flowering cherry Prunus ¥incam Ingram (Rosaceae).  Novon 19: 490-493.

2011.  A. T. Whittemore and R. Olsen.  Ulmus americana is a polyploid complex.  American Journal of Botany 98: 754-760.

2012. A. T. Whittemore. Cannabaceae and Celtis. Pp. 598-600 in The Jepson Manual: Higher Plants of California ed. 2. Berkeley: University of California Press.

2012. A. T. Whittemore. Shepherdia. Pp. 682-684 in The Jepson Manual: Higher Plants of California ed. 2. Berkeley: University of California Press.

2012. A. T. Whittemore. Juglandaceae. Pp. 832-833 in The Jepson Manual: Higher Plants of California ed. 2. Berkeley: University of California Press.

2012. E. McClintock and A. T. Whittemore. Moraceae. Pp. 910-911 in The Jepson Manual: Higher Plants of California ed. 2. Berkeley: University of California Press.

2012. E. McClintock and A. T. Whittemore. Pittosporaceae. Pp. 1000-1001 in The Jepson Manual: Higher Plants of California ed. 2. Berkeley: University of California Press.

2012. A. T. Whittemore. Myosurus. Pp. 1142-1144 in The Jepson Manual: Higher Plants of California ed. 2. Berkeley: University of California Press.

2012. A. T. Whittemore. Ranunculus. Pp. 1144-1150 in The Jepson Manual: Higher Plants of California ed. 2. Berkeley: University of California Press.

2012. A. T. Whittemore. Sapindaceae and Acer. Pp. 1230-1231 in The Jepson Manual: Higher Plants of California ed. 2. Berkeley: University of California Press.

2012. A. T. Whittemore. Ulmaceae. Pp. 1260-1262 in The Jepson Manual: Higher Plants of California ed. 2. Berkeley: University of California Press.

2012. A. T. Whittemore. Proposal to conserve the name Celtis glabrata Steven ex Planch. (Cannabaceae) with a conserved type. Taxon 61: 254-255.

In press. B. Parfitt and A. T. Whittemore. Ranunculus. In Flora of the Four Corners Region: Vascular Plants of the San Juan River Drainage, Arizona, Colorado, New Mexico, Utah, ed. K.D.Heil, S. O'Kane, and L. Reeves. Missouri Botanical Garden Press, St. Louis.

In press. B. Parfitt and A. T. Whittemore. Myosurus. In Flora of the Four Corners Region: Vascular Plants of the San Juan River Drainage, Arizona, Colorado, New Mexico, Utah, ed. K.D.Heil, S. O'Kane, and L. Reeves. Missouri Botanical Garden Press, St. Louis.

In press. B. Parfitt and A. T. Whittemore. Ceratocephala. In Flora of the Four Corners Region: Vascular Plants of the San Juan River Drainage, Arizona, Colorado, New Mexico, Utah, ed. K.D.Heil, S. O'Kane, and L. Reeves. Missouri Botanical Garden Press, St. Louis.

In press. B. Parfitt and A. T. Whittemore. Aquilegia. In Flora of the Four Corners Region: Vascular Plants of the San Juan River Drainage, Arizona, Colorado, New Mexico, Utah, ed. K.D.Heil, S. O'Kane, and L. Reeves. Missouri Botanical Garden Press, St. Louis.

In press. A. T. Whittemore. Fagaceae. Flora of Missouri, volume 3.

In press. A. T. Whittemore. Juglandaceae. Flora of Missouri, volume 3.

In press.  A. T. Whittemore.  Moraceae.  Flora of Missouri, volume 3.

In press. A. T. Whittemore. Platanaceae. Flora of Missouri, volume 3.

In press.  A. T. Whittemore.  Hamamelidaceae.  Flora of Missouri, volume 3.

In press. A. T. Whittemore. Leitneriaceae. Flora of Missouri, volume 3.

In press. A. T. Whittemore. Menispermaceae. Flora of Missouri, volume 3.

In press. A. T. Whittemore. Ranunculaceae. Flora of Missouri, volume 3.

In press. A. T. Whittemore. Ulmaceae. Flora of Missouri, volume 3.

In press. A. T. Whittemore and E. McClintock. Pittosporaceae. Flora of North America vol. 13. Prepublication posting at fna.huh.harvard.edu/files/Pittosporaceae.pdf

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