New Combinations of East Asian Species of Polygonum Sl
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植物研究雑誌 J. J. Jpn. Bo t. 72: 72: 154-161 (1 997) New Combinations of East Asian Species of Polygonum s. l. Koji Koji YONEKURA and Hiroyoshi OHASHI Biological Biological Institute ，Graduate School of Science ， Tohoku University ， Aoba ，Sendai ，Miyagi ， 980-77 JAPAN (Received (Received on January 1， 1997) Classification Classification systems of P olygonum s. 1. applied to East Asian species are compared ， andcircumscriptions andcircumscriptions of Persicaria andFallopia are discussed. New combinations forthe species species of Aconogonon (one variety of A. molle) ，Bistorta (five species) ，Fallopia (one species species and five varieties) and Persicari α(four species and two varieties) previously included included in Polygonum s. 1. in East Asia are proposed. Polygonum L. (1753) is characterized by are some disaccordance between two systems herbaceous herbaceous or undershrubby habit ，4-5 parted proposed by Haraldson (1 978) and Ronse persistent persistent perianths ，6-8 stamens ，2 or 3 styles Decraene and Akeroyd (1 988) in the generic usually usually with capitate stigmata ，and lenticular circumscription of some genera ，especially or or trigonous achenes (Bentham and Hooker those of P ersicaria Mill. and F allopia Adans. 1880 ，Dammer 1894). Boundaries between The Asian species of Polygonum in the Polygonum and its allied genera (i.e. ， broad sense have been classified into many Atraphaxis ，Koenigia ，Muehlenbeckia ， small genera ， but circumscriptions of some Polygonella ，etc.) are ，however ，notclear. Many genera are different from each other as shown botanists botanists have tried to constract a natural sys- in Table 1. On the other hand; the traditional tem by dividing Polygonum into more natural system ofkeepingPolygonum s. 1. as adistinct smaller smaller genera and consequently various sys- genus has also been firmly adopted in floras in tems have been proposed (e.g. ， Gross 1913a ， East Asia (Steward 1930 ，Ohwi 1953 ，1965 ， 1913b ，Nakai 1926 ， Roberty and Vautier 1956 ， Kitamura and Murata 1961 ， Li 1983 ，1993 ， Sojak Sojak 1974 ， Haraldson 1978 ， Tzvelev 1987 ， Kuo et a1. 1996). We agree with them to divide Ronse Decraene and Akeroyd 1988). Polygonum s. l. into several small genera. In Recent studies on morphology and anatomy this paper ，various systems hitherto applied to of of Polygonum S. 1. by Haraldson (1 978) and by East Asian species of Polygonum s. l. are Ronse Decraene and Akeroyd (1 988) revealed compared in the viewpoint of dividing this that that this genus is not monophyletic ，and the genus ，and discussed about the problem of diagnostic diagnostic characters for Polygonum s. 1. are circumscriptions of genera Persicaria and considered considered to be plesiomorphic rather than Fallopia. New combinations of East Asian apomorphic. apomorphic. Haraldson (1 978) and Ronse species based on this concept are proposed. Decraene and Akeroyd (1 988) therefore over- 1. Circumscription of Persicaria Mill. tumed previous concepts of Polygonum s. 1. Haraldson (1 978) included Aconogonon ， and divided it into eight genera in three tribes Bistorta ，Koenigia ，and Persicaria (had been orfive orfive generain twotribes ，respectively. There thought to be unrelated genera) into the tribe 一-154 一一 June 1997 Jouma1 of Japanese Botany Vo 1. 72 No. 3 155 Table Table 1. Comparison of systems of Polygonum s. l. with representative Asian species Hedberg (1946) autier P. P. chillense P. P. perfoliatum P. P. sellticosum P. P. sagittatum P. P. orientale P. P. amphibium P. P. persicaria Polygonum P. 戸liforme P.pO ちか加ぽyst ωα ， ch 仰J P. P. divaricatum P. P. weyrichii P. P. sibiricum P. P. bistorta P. P. cOllvolvulus P. P. mult 抑orum P. P. cuspidatum P. P. aviculare P. P. Hara (1966) I S吋ak (1974) I Haraldson (1978) I Tzvelev (1987) Koenigia Koenigia Hatched Hatched areas indicate Persicaria as a genus. X; plants did not treated by the author(s) in the paper. illegitimate *; illegitimate names. Persicarieae Persicarieae on the basis of some distinct ana- Koenigia andPersic αria as distinct genera and tomical tomical characters of petiole and stem. Her treated Aconogonon and Bistorta as sections opinion opinion was supported by Ronse Decraene of the genus P ersicaria. They also included and Akeroyd (1988) ， but they recognized genera Fagopyrum and H αrpagoc α rpus into 156 156 植物研究雑誌第72 巻第3号 平成9年6月 Persicarieae ，which were regarded by ent with base of filaments of inner wheel Haraldson Haraldson (1978) as a member of the tribe (Ronse Decraene and Akeroyd 1988; Ronse Polygoneae Polygoneae and Coccolobeae respectively. Decraene and Smets 1991) ， and the tricolporate Aconogonon ，Bistorta ，Koenigia ，and pollen grains with minutely punctate and ersicaria P ersicaria had often been treated as distinct microspinulose exine scruptures and with genera genera from Polygonum L. before Haraldson densely packed collumerae (Nowicke and (1978) (1978) (e.g. ， Gross 1913a ，1913b ， Nakai 1926 ， Skvarla 1987). Moreover ，no hybrids have Hara 1966 ， Sojak 1974). In addition ， such been reported between Bistorta and related small small groups are regarded to be distinct as genera. In this reason we recognize Bistorta as Antenoron Raf. by Steward (1930 ， as Tovara a distinct genus from P ersicari α. Adans. ，now nom. r吋ic.) ， Roberty and Vautier Polygonum filiforme ， P. neofiliforme of (1954) (1954) and Hara (1 966) ， and Truellum Hout t. eastem Asia ， and P. virginianum of eastem by Sojak (1974) ， but these were not treated as N orth America have been frequently treated as distinct distinct by Haraldson (1 978) because their constituting an independent genus Antenoron diagnostic diagnostic characters were regarded as insuf- Raf. because of its unique hook -like persistent ficient ficient for generic division. On the other hand ， styles ， reduced number of tepals and stamens ， Tzvelev Tzvelev (1987) splitted P ersicaria in the sense and distinct 12-colpate pollen aperture type of of Haraldson into five genera ，i.e. ， Antenoron (Nakai 1926 ， Steward 1930 ， Roberty and Raf. ，Cephalophilon Spach ， Chylocalyx Hass k. Vautier 1956 ，Hara 1966). Gross morphologi- exMiq. ，Persicaria s. st r.， and TruellumHout t. cal characters of these species are ，however ， Tzvelev Tzvelev (1987) also proposed a new genus very similar to the genus P ersicaria and some Knorringia Knorringia (Czu k.) Tzve l. basedonPolygonum microcharacters used to distinguish these spe- sibiricum sibiricum Laxm. and P. pamilicum Korsh. ， cies from P ersicaria have proved unclear which were regarded as a member of (Haraldson 1978). Moreover ， according to a Polygonum sec t. Aconogonon (Steward 1930) cladistic analysis made by Hong (1 993) ， or or Aconogonon (Hara 1966). Hong (1989) P ersicaria includingAntenoron and some other supported supported this generic status and treated this small groups recognized by Tzvelev (1 987) as genus genus as belonging to a tribe Coccolobeae ， not distinct genera constituted a monophyletic to to Persicarieae. group. Hong (1 989 ，1992 ， 1993) revealed the bor- As discussed above ，we follow Haraldson der der between Aconogonon and Persicaria (1 978) and Hong (1993) and recognized clearer clearer than that of Ronse Decraene and Aconogonon (exceptKnorringi α) andBistorta Akeroyd (1988) and recognizedAconogonon as distinct genera from Persicaria ， but such as as a distinct genus. We agree with his opinion groups as Antenoron ，Cephalophilon ，and for for the treatment of Aconogonon. Ronse Truellum are treated as sections of Persicaria Decraene Decraene and Akeroyd (1 988) treatedBistorta and not regarded as distinct genera. as as a section of Persicaria ，butBistorta has not 2. Circumscription of F allopia Adanson only only distinct gross morphology ，i.e. ， the Fallopia Adans. in the broad sense is char- lignified lignified rhizome or prostrate stem and the acterized by existence of extrafloral nectaries ， spike-like spike-like pseudoraceme ，which have been keeled outer tepals ，dendricular tepal vena- traditionally traditionally used as the diagnostic characters tion ，filaments dilated at base and usually of of this genus ， but also some other characteris- covered with papillae ， and fimbriate stigma (in tics tics such as the anatomical character of leaf some species) (Ronse Decraene and Akeroyd petiole petiole (Haraldson 1978) ， the nectaries coher- 1988). Other various generic names ，i.e. ， June June 1997 Joumal of Japanese Botany Vo l. 72 No. 3 157 Reynoutri α (1 777) ，Bilderdyki α (1 827) ， E. Hima 1. 68 (1 966) ， ut Aconogonum. Tiniaria Tiniaria (1 837) ， or Pleuropterus (1 848) had Polygonum molle D. Don ，Prod r. F1. Nepa 1. been used to this group before Holub (1970) 72 (1 825). mentioned the priority of Fallopia (1 763). Persicaria mollis (D. Don) H. Gross in Three different concepts have been proposed Bull. Geogr. Bo t. 23: 31 (1 913). on the classification of F αllopia after Nakai va r. paniculatum (Blume) Y onekura & H. (1 926) (Table 1): Nakai (1 926) recognized Ohashi ，comb. nov. three three generaBilderdykia ， P leuropterus Turcz. ， Polygonum paniculatum Blume ，B りdr. 533 and Reynoutria Hout t. in this group on the (1 825). basis basis of gross morphology (twining vs. erect Aconogonon paniculatum (Blume) habit) ， shape of stigma and pollen scrupture ， Haraldson in Symb. Bo t. Upsa 1. 22(2): 69 and his treatment was followed by Hara (1966) (1 978). and Kitagawa (1979 ， 1982). On the other hand ， Polygonum frondosum Meisn. in DC. Hedberg (1946) and Ronse Decraene and Prod r. 14: 137 (1 856). Akeroyd (1 988) united these genera and rec- Polygonum paniculatum va r.斤 ondosum ognized ognized one genus in this group. Haraldson (Meisn.) Stewardin Contr. Gray Herb. Harvard (1978) (1978) recQgnized two genera F αllopia and Univ.88: 196 (1930). Reynoutria Reynoutria on the basis of gross mo 中hology ， Aconogonon molle va r. frondosum anatomical anatomical character and stigma shape ，and (Meisn.) H. Hara ， F 1. E. Hima 1. 68 (1 966); in Tzvelev (1 987) followed her treatmen t. Hara et a1.， Enum. F1. P1. Nepa13: 187 (1 982); Ronse Decraene and Akeroyd (1988) united Hong in Symb. Bo t. Upsa 1. 30(2): 87 (1 992).