Revision of Fothergilla (Hamamelidaceae), including resurrection of F. parvifolia and a new species, F. milleri

Jake E Haynes; Whitney D Phillips; Alexander Krings; Nathan P Lynch; Thomas G Ranney

doi:10.3897/phytokeys.144.49589

Revision of Fothergilla (Hamamelidaceae), including resurrection of F. parvifolia and a new species, F. milleri

PhytoKeys. 2020 Mar 17:144:57-80. doi: 10.3897/phytokeys.144.49589. eCollection 2020.

Authors

Jake E Haynes¹, Whitney D Phillips^{2

3}, Alexander Krings¹, Nathan P Lynch^{2

3}, Thomas G Ranney^{2

3}

Affiliations

¹ Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
² Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695, USA.
³ Mountain Horticultural Crops Research and Extension Center, Mills River, NC 28759, USA.

Abstract

Fothergilla is a small genus of deciduous shrubs native to the southeastern United States that depending on circumscription comprises two to four species. Recent treatments recognized only two species in the genus: F. gardenii (tetraploid) and F. major (hexaploid). Until recently, no diploid taxon of Fothergilla was known. However, recent investigations identified a number of diploid populations in Alabama, Florida, Georgia, and South Carolina. A subsequent phylogenomic analysis showed that the diploids segregated into two, well-supported lineages, corresponding to largely allopatric populations. A re-examination of the morphology of diploid plants, in combination with the genetic evidence, has led us to the recognition of two species of diploids in the genus - a resurrected F. parvifolia and a new species (F. milleri W.D. Phillips & J.E. Haynes, sp. nov.) - bringing the total number of recognized species in Fothergilla to four. A revised taxonomic treatment of the genus is provided.

Keywords: Hamamelidoideae; Coastal Plain; Fothergilleae; southeastern United States.

Jake E. Haynes, Whitney D. Phillips, Alexander Krings, Nathan P. Lynch, Thomas G. Ranney.

Grants and funding

This work was supported by the North Carolina Agricultural Research Service, North Carolina Cooperative Extension, Mt. Cuba Center, USDA-ARS Woody Landscape Germplasm Repository, the Birmingham Botanical Gardens, and the National Institute of Food and Agriculture, U.S. Department of Agriculture, acc. nos. 62303, 1002682, and 1006920 (project no. NC02559).