New Infrageneric Taxa and Combinations in Chenopodium L. (Chenopodiaceae) Sergei L. Mosyakin N. G. Kholodny Institute of Botany, 2 Tereshchenkivska Str., Kiev, 252601 Ukraine Steven E. ClemantsBrooklyn Botanic Garden, 1000 Washington Avenue, Brooklyn, New York 11225-1099, U.S.A.ABSTRACT. Five new subsections and five newcombinations of subsectional rank are validatedwithin Chenopodium subg. Blitum (L.) Hiitonen andChenopodium L. subg. Chenopodium. In subgenusBlitum these are: Chenopodium subsect. Foliosa Ko-wal ex Mosyakin & Clemants; and Chenopodiumsubsect. Capitata Kowal ex Mosyakin & Clemants.In subgenus Chenopodium the new subsections are:Chenopodium subsect. Polysperma Kowal ex Mosy-akin & Clemants; Chenopodium subsect. UndataAellen & Iljin ex Mosyakin & Clemants; and Che-nopodium subsect. Standleyana Mosyakin & Cle-mants. The new combinations in subgenus Cheno-podium are: Chenopodium subsect. Urbica (Standley)Mosyakin & Clemants; Chenopodium subsect. Lep-tophylla (Standley) Clemants & Mosyakin; Cheno-podium subsect. Fremontiana (Standley) Clemants &Mosyakin; Chenopodium subsect. Favosa (Aellen)Mosyakin & Clemants; and Chenopodium subsect.Cicatricosa (Aellen) Mosyakin & Clemants. Delimi-tation of some other infrageneric taxa is discussed. The genus Chenopodium L. (Chenopodiaceae)may be subdivided into three natural subgenera:Chenopodium subg. Ambrosia A. J. Scott, subg. Bli-tum (L.) Hiitonen, and subg. Chenopodium. There has been a fair amount of debate aboutthe proper type for Chenopodium. Britton andBrown (1913) were the first to select a lectotype (C.rubrum L.), but Hitchcock and Green (1929) adopt-ed C. album L. as the lectotype. This later choicehas been accepted in recent literature (Jarvis et al.,1993; Greuter et al., 1993; for additional argumentssee Uotila, 1993; Mosyakin, 1993), and is thus fol-lowed in this paper as well. The infrageneric taxonomy of the genus has beenextensively discussed in several publications (Stan-dley, 1916; Aellen & Iljin, 1936; Kowal, 1953; Ael-len, 1960; Scott, 1978). However, in preparingtreatments of Chenopodium for forthcoming vol-umes of the Flora Europae Orientalis (Mosyakin),the Flora of North America, and the Flora of JapanNovoN 6: 398-403. 1996.(Clemants) it has become evident that new infra-generic taxa and combinations should be validatedwithin Chenopodium subg. Blitum and Chenopodi-um subg. Chenopodium.Chenopodium subg. Blitum (L.) Hiitonen, Suo-men Kasvio: 307. 1933. TYPE: Blitum capi-tatum L. (= Chenopodium capitatum (L.) Am-brosi (lectotype of the genus Blitum L., selected by Britton & Brown, 1913). If Chenopodium rubrum were considered the lec-totype of Chenopodium, then this would have to be called Chenopodium subg. Chenopodium. However, if the genus Blitum is recognized, this lectotypifi-cation of Chenopodium by C. rubrum may cause serious disruption in the nomenclature of the ma-jority of species currently placed in Chenopodium. Ignatov (1988) redundantly made the same com-bination at the subgeneric level.Chenopodium [sect. Blitum (L.) Hooker fil.] sub-sect. Foliosa Kowal ex Mosyakin & Clemants, subsect. nov. Chenopodium sect. Eublitum (Mo-quin-Tandon) Aellen subsect. Foliosa Kowal, Monogr. Bot. (Warszawa) 1: 113. 1953 (invalid name: Polish description); Aellen in Hegi, I1-lustr. Fl. Mitteleur., ed. 2, 3/2: 577. 1961 (in-valid name: German description). TYPE: C. fo-liosum Ascherson (= Blitum virgatum L.). Perianthii segmenta in fructus tempore succulenta (rar-ius exsucca). Semen margine canaliculatum vel obtusa-tum. Inflorescentia plerumque foliosa. Perianth segments succulent at maturity, formingcharacteristic berry-like clusters (rarely non-suc-culent). Seeds with canaliculate or obtuse margins.Inflorescence normally leafy (flowering clusterswith subtending leaves/bracts almost to the top). This subsection includes the C. foliosum aggre-gate: C. foliosum s. str., C. exsuccum (Loscos) Uoti-la, C. litwinowii (Paulsen) Uotila (= C. korshinskyi
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