Phytologia (February 1994) 76(2):176-184. /lP0Py7?0S(ASTERACEAE: ASTEREAE), A NEW GENUS FROM SOUTHERN BRAZIL, ARGENTINA. AND PARAGUAY Guy L. Nesom Department of Botany, University of Texas, Austin, Texas 78713 U.S.A. ABSTRACT Two species of southern Brazil Jind adjacent Paraguay and Ar-gentina, formerly identified as Aster and Conyza, are here treated as Apopyros Nesom, gen. nov., with the new combinations Apopyros warmingii (Bciker) Nesom and Apopyros corymbosus (Hook. & Am.) Nesom. Apopyros is hypothesized to be most closely related to species of three other genera with a similar austro-brasilien geo-graphic distribution in east-central South America: Leptostelma, Neja, and Hysterionica. In their parallel-veined leaves with shiny-indurate surfaces, multinerved, nearly terete achenes, and tendency to produce stiffly pilose-hirsute vestiture, Neja and Apopyros are distinctive among their close relatives. KEY WORDS: Apopyros, Aster, Asteraceae, Astereae, South Amer-ica Aster warmingii Baker and Dtplopappus corymbosus Hook. &; Arn. (= Aster tuberosus Less. = Aster seiosus Baker = Conyza blanchetii Baker, see below) are perennial herbs endemic to south-central Brazil, where at least the first species has often been encountered in periodically burned cerrados. Aster waTmtngti was described after Bentham's systematic overview of the tribe (1873), and neither species was specifically included in Hoffmann's subsequent review of the tribe (1890). Nor, apparently, has either been subject to any other critical tajconomic evaluation since their first recognition. Clearly, they do not belong with any group of Aster, even in the broadest sense of that genus (Nesom in prep.). In the interpretation here. Aster warmmgii and D. corym-bosus are recognized as a separate genus closely related to three other genera that occur in the same region of east-central South America: Leptostelma D. Don (Nesom in press), Neja D. Don (Nesom 1994), and Hysterionica Willd. 176
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