Switchgrass Karyogram and Condensation Pattern (CP). Mitotic prometaphase chromosome spreads were stained with acetocarmine, resulting in uneven condensation patterns (a). Homoeologous chromosomes were paired based on length, arm ratio, and CP data to develop a karyogram. The basic chromosome number of n = 9 is indicated (b). CP measurements were averaged for each chromosome across 10 mitotic spread images, resulting in a quantitative ideogram (c). Dark regions indicate highly-condensed heterochromatic areas, gray indicates intermediate condensation, and white indicates euchromatic areas. Scale bars = 5 μm.