Phytotaxa 314 (2): 151–194 ISSN 1179-3155 (print edition) http://www.mapress.com/j/pt/ PHYTOTAXA Copyright © 2017 Magnolia Press Article ISSN 1179-3163 (online edition) https://doi.org/10.11646/phytotaxa.314.2.1 Persepolium (Polygoneae): A new genus in Polygonaceae based on conventional Maximum Parsimony and Three-taxon statement analyses of a comprehensive morphological dataset OLGA V. YURTSEVA1*, ELENA E. SEVEROVA1 & EVGENY V. MAVRODIEV2 1Department of Higher Plants, Faculty of Biology, M.V. Lomonosov Moscow State University, 1–12, Leninskie Gory, 119234, Moscow, Russia; e-mail:
[email protected] 2Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, U.S.A. *Author for correspondence Abstract Recent molecular studies revealed the polyphyletic nature of the broadly defined genus Polygonum. This paper includes a standard maximum parsimony (MP) and three-taxon statement analyses (3TA) as well as a taxonomic revision of Polygonum sect. Avicularia subsect. Spinescentia (Polygonaceae) as compared with two closely related taxa: genus Atraphaxis s.s., and genus Bactria. In total, 27 characters, including life history, habit, morphology of the shoots, leaf blades, ocreas, perianth, achene, ultrasculpture of perianth and achene surfaces, as well as pollen morphology, were analyzed, illustrated, and dis- cussed in detail. Both the standard MP and 3TA confirm that monophyletic Polygonum subsect. Spinescentia is sister to the narrowly defined Atraphaxis. The genus Persepolium (Polygonum subsect. Spinescentia), with the circumscription of five species, is established as new to science as a result of this study. Possible transformations of perianth and thyrse morphology are discussed within the framework of the Principle of variable proportions by Troll in connection with a shift of pollination mode in the group of taxa studied.