Legend variations

par(mar=c(5.1,4.1,4.1,11.1))
plot( x=1:5, y=1:5, type="n", xlab="x", ylab="y" )

legend( x=2, y=6, legend=c("A","B","C")
  , fill=c("red","blue","green")
  , density=30, bty="n", horiz=TRUE
  , xpd=TRUE )

legend( x=2, y=2, xjust=0.5, yjust=0
  , title=" My title:", title.col="grey40", title.adj=0
  , legend=c("A","B","C","D","E")
  , pch=c(22,22,22,45,45), pt.cex=c(1.2,1.2,1.2,2,2)
  , col=c(rep("black",3),"orange","red")
  , pt.bg=c("blue","green","yellow")
  , bg="grey95", cex=0.8
  , box.col="darkgrey", box.lwd=3, box.lty="dotted" )

legend("topright", inset=0.05, cex=0.8, bg="white"
  , legend=c("A-1","A-2","B-1", "B-2")
  , col=c("lightblue","blue","salmon","red"), pch=15, pt.cex=1.5
  , y.intersp=1.5, x.intersp=1.5 , ncol=2 )

windowsFonts("sans2"="Arial Black")
usr <- par(font=4, family="sans2" )
legend( x=5.5, y=3, legend=c("Label A","Label B","Label C")
  , fill=c("red","orange","yellow")
  , border="brown"
  , y.intersp=2, text.width=strwidth("Make larger")
  , text.col=c("red","orange","yellow")
  , xpd=TRUE )
par(usr)

legend( x="bottomleft", inset=0.02, legend=c("A","B","C","D")
  , lty=c("dashed","dotted",NA,"solid"), lwd=2, cex=0.8
  , pch=c(NA,NA,21,15)
  , col=c("red","blue","black","grey"), bg="white" )