Misconfigured legends

Question

I use the following script and I obtain a missconfigured legends. Do you know the reason?

barplot(x, main="Especies y Grupos", beside=TRUE, col=c("red","green3","blue"), xlab="Grupos", ylab="Frecuencia")

Añadir la leyenda en la parte superior izquierda

legend("topleft", legend=rownames(x), fill=c("red","green3","blue"))

enter image description here

Thank you very much in advance!

Configure the legend plot and put in the side correct