Hi, I've got a data.frame object which I would like to plot in a lattice xyplot grouped by a variable and using a value for the color of each point which is stored in a variable in the same data.frame. I tried the following code: my.panel.xy <- function(x, y, ...){ panel.xyplot(x, y, ...) panel.lmline(x, y, lwd = 2) panel.abline(0, 1, col="red", lty=2) panel.grid(h = -1, v = -1, lty=1) } xyplot(log(AGB) ~ log(BM_roots) | as.character(taxa), data=sub_agb_data,main=list("AGB in dependence of BM_root [per taxa!]",cex=0.7), ylab=list("log(AGB)",cex=0.7),xlab=list("log(BM_root)",cex=0.7),col=sub_agb_data$color, panel = my.panel.xy) xyplot(log(AGB) ~ log(BM_roots) | as.character(species), data=sub_agb_data,main=list("AGB in dependence of BM_root [per species!]",cex=0.7), ylab=list("log(AGB)",cex=0.7),xlab=list("log(BM_root)",cex=0.7),col=sub_agb_data$color, panel = my.panel.xy) Somehow the colors are not displayed correctly (it works if I use plot in a for loop for each value for the variables for which I group my lattice plots. The color variable is of type character so this shouldn't be the reason) The object sub_agb_object can be downloaded here: http://www.wzw.tum.de/oekophys/fileadmin/sub_agb_data.rData Maybe somebody has any idea how to make this work or what the problem might be? Thanks, Katharina