either a vector or matrix of values describing the bars which make up the plot exactly as used for creating the barplot.
b
the returned mid points as returned by b <- barplot(...).
labels
the labels to be placed on the bars.
beside
a logical value. If FALSE, the columns of height are portrayed as stacked bars, and if TRUE the columns are portrayed as juxtaposed bars.
horiz
a logical value. If FALSE, the bars are drawn vertically with the first bar to the left. If TRUE, the bars are drawn horizontally with the first at the bottom.