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POLYGONUM RURIVAGUM AVICULARE SUBSP. NORTH AMERICA (POLYGONACEAE) IN Department of Plant Agriculture Department of Plant Agnculture ofGueiph ofQuelph University University Guelph, Ontario,NlG2Wi, CANADA Guelph, Ontario, Ni G 2Wl CANADA [email protected] [email protected] ABSTRACT ibsp.runvaguminNorthA Non de Polygonum aviculare subsp. rurivagum en a de Europa que crece en lugares ruderales, soleai irio The occurrence the European Polygonum aviculare subsp. rurivagum of L. (Jord. ex Boreau) Berher in North America has been uncertain. Love and Love (1956) reported from eastern North America but they did not indicate any location. it some Furthermore, have been generally disregarded because of their results chromosome and no specimens vouchers have been doubtful counts, because or & & quoted or found Mertens Raven 1965; Wolf McNeill 1986). During the (e.g., we preparation of the genus Polygonum for Flora of North America have en- North America and we compared countered this taxon in scattered locations in with European material. Some relatively recent European floras and treat- it rurivagum ments of Polygonum have preferred to treat this taxon as a species (P & Akeroyd Do Amaral Franco Da Luz Rocha Afonso ex Boreau, 1993; Jord. e.g., followmg study Nevertheless, 1995; Stace 1997) the of Styles (1962). its classifi- cation under P aviculare apparently the best solution (Karlsson 2000; Costea is & homogenous extreme morphology, with Tardif 2003). a rare but taxon. Its It is mm, and paucif lorous cymes (1-3 flowers), small flowers, 2.3-3.2 narrow-ellip- mm P tic to linear-lanceolate leaves, 1.5-5 wide, brings it close to aviculare subsp. neglectum (Besser) Arcang., with which has been frequently misidentified. it mm, The subsp. rurivagum differs by the long ochreas, 8-12.5 with strong veins and the free part disintegrating into persistent fibers, and by the leaves with The veins strongly raised on the abaxial part of the leaves. subspecies lateral mm, 4-8 and neglectum has ochreas of with inconspicuous veins free part leav- ing almost no fibrous remains and leaves without strongly raised lateral veins. For differences between subsp. rurivagum and the other subspecies of P. civuuUirc Irom North America see Costea and Tardif (2003). For iconography sec RalTaelli (1982, Fig. 12), Karlsson (2000, Fig. 96). The plant grows as a rud- cral in dry sunny and often trampled habitats in pavement cracks gravel and sand\ places Flowering occuis fiom June Octobei to We warmly thank James and Reveal Cecil Slaughter, providing Jr for critical We ACAD, edits to earlier drafts of the manuscript. also thank the curators from DAO, MTMG, ALTA, CAS, DC, DS, GH, JEPS, LL, MT, NFLD, NSPM, NY, PO, F, UC QFA, QUE, RSA, SASK, TEX, UBC, and US preparing S, for the (usually) vo- luminous Polygonum loans. Laura Echarte checked the Spanish translation of Edmondson,V.H. Europaea Flora Is. \ . Do Amaral Franco, and M. Da Luz Rocha Afonso. 1995. Especies da sect, Pc J. em 53-1 existentes Portugal. Stud. Bot. 4:1 75. 1 and 956. Chromosomes and taxonomy of eastern North Love, a. D. Love. / 1 Polygonum. Canad. 34:501-521 Bot. J. genus Po/ygoDum Nordica KARLssoN,T.2000.The L.ln:Jonsell,B.ed., Flora vol.1, St' 255-273. Pp. Taxonomy Polygonum Polygonum MERTENsJ.R.and RH. Raven. 1965. of section {A conoscenza genere Polygonum sped 982.Contributi del L.4.Le Raffaelli,M. alia 1 Webbia Po/ygonum. 35:361-406. della sectia New Cambridge Stace,C.A. 1997. flora of British lsles,2nd ed., University Press,Ca The taxonomy Polygonum and Styles, B.T. 1962. of aviculare its allies in Britain. 5:177-214. Wolf, and McNeill. 986. Synopsis and achene morphology of Polygonun S.J. J. 1 Polygonum (Polygonaceae) Canada. Rhodora 88:457-479. in