01148nas a2200145   4500008004100000245015900041210006900200300001300269490000700282520061100289100001900900700001700919700001700936856004900953       1997                        eng d00aEvolutionary implications of meiotic chromosome behavior, reproductive biology, and hybridization in 6X and 9X cytotypes of Andropogon gerardii (Poaceae )0 aEvolutionary implications of meiotic chromosome behavior reprodu  a201 -2070 v843 aAndropogon gerardii, big bluestem, has 60 and 90 chromosome cytotypes. Meiosis in the hexaploid was shown to be regular, although some secondary associations of bivalents form. Meiosis in the enneaploid (2n = 9z = 90) is irregular, leading to most gametes having unbalanced chromosome complements. Both cytotypes show considerable self-incompatibility. Cytotypes crossed freely, forming a variety of fertile euploids and aneuploids. Indistinguishable exomorphology, intermixing in natural populations, and compatibility suggest that A. gerardii is best understood as a cytotypically complex single species.1 aNorrmann, G.A.1 aQuarin, C.L.1 aKeeler, K.H.  uhttp://www.amjbot.org/content/84/2/201.short