title: Remove points from a plot without removing the lines
body: <p>is there someone who knows how to remove the points without removing the line in a plot?</p>
  
  <p>I have created a plot like the last one in the link bellow with a binomial scale.</p>
  
  <p>Yes the points are informative but when adding more lines in the plot and concentrating on the different trends for the different lines the points feels a bit needless. And second just being curious how to alter the appearance in a plot. </p>
  
  <p><img src="https://i.stack.imgur.com/OnhS2.png" alt="binomial scale"></p>
  
  <p>The commandos i have used is:</p>
  
  <pre><code>&gt; plot(Leaves&gt;0~light,x,xlab="Light",ylab="Response")
  
  &gt; g=glm(formula = Leaves &gt; 0 ~Light, family = binomial ,data =V.riviniana, na.action = na.exclude)
  
  &gt; curve(predict(g,data.frame("Light"=x),type="resp"),add=TRUE,lty=8)
  
  &gt; g2=glm(formula=Leaves&gt;0~Light, family=binomial, data=V.biflora,na.action=na.exclude)
  
  &gt; curve(predict(g2,data.frame(Light"=x), type="resp"),add=TRUE,lty= 1)
  </code></pre>