DARWINIANA

34(1-4): 213-231. 1996

ESTUDIOS CARIOLOGICOS EN COMPOSITAE VII1

ARTURO F. WULFF 2

Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, U. B. A., (1428) Buenos Aires, Argentina

JUAN H. HUNZIKER 3

Instituto de Botánica Darwinion, Casilla de Correo 22, (1642) San Isidro, Argentina

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Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, U. B. A., (1428) Buenos Aires, Argentina

ALEJANDRO ESCOBAR 2

Instituto de Botánica Darwinion, Casilla de Correo 22, (1642) San Isidro, Argentina

ABSTRACT: Wulff, A. F., J. H. Hunziker & A. Escobar, 1996. Karyological studies in Compositae VII. Darwiniana 34: 213-231.

Meiotic and/or mitotic chromosome numbers were determined and observations on meiotic behavior were made in 104 accessions belonging to 75 species and 32 genera distributed in 10 tribes of the Asteraceae. One genus (Picrosia), 21 species and 2 varietes are investigated cytologically for the first time. These are as follows, tribe Mutisieae: Chaptalia graminifolia (Dus.) Cabrera and Ch. pilloselloides (Vahl.) Baker (2n = ca. 48); tribe Cichorieae: Picrosia longifolia Don (n = 7 II); tribe Astereae: Baccharis effusa Griseb. (n = 9 II), B. flabellata (n = 9 II), B. flabellata var. argentina (Heer.) Ariza (n = 9 II), B. rhexioides H. B. K. (n = 9 II), B. tucumanensis Hook. et Arn. (n = 9 II), Grindelia buphthalmoides DC. (2n = 12); tribe Senecioneae: Senecio flagellisectus Griseb. (n = 20 II), S. grisebachii Baker var. grisebachii Baker (n = 20 II), S. lorentzii Griseb. (n = 20 II); tribe Heliantheae: Calea clematidea Baker (n = 19 II), Cosmos marginatus Klatt (n = 24 II), Spilanthes alpestris Griseb. (n = ca. 14 II), Tridax paraguayensis Kuntze (n = 18 II); tribe Eupatorieae: Eupatorium buniifolium Hook et Arn. (2n = 20 + B), E. lorentzii Hieron. (n = ca. 17 II), E. grosidentatum Hieron. (n = 10 II), Ophryosporus macrodon Griseb. (n = 10 II), Pterocaulon lanatum O. K. (n = 11 II), Stevia aff. effusa Hieron. (n = 11 II) and S. maimarensis (Hieron.) Cabrera (n = 11 II).
Different chromosome numbers to those reported previously in the literature were found for Aspilia montevidensis (Spreng.) Kuntze var. setosa (Griseb.) Cabrera (n = 11 II), Liabum polymnoides R.E. Fries (n = 15 II) and E. saltense Hieron. (n = ca. 26 II) The karyotypes of Hieracium tandilense Sleumer, Baccharis effusa Griseb., B. spicata (Lam.) Baillon, Eupatorium buniifolium Hook. et Arn. and Stevia satureaiefolia (Lam.) Schultz-Bip. are described for the first time.
The significance of some of the results in relation to taxonomical and evolutionary problems is discussed.

1 Darwiniana 30(1-4): 115-121. (1990) 1991
2 Miembro de la Carrera del Personal de Apoyo (CONICET)
3 Miembro de la Carrera del Investigador Cientpifico y Tecnológico (CONICET)