title: rotate the labels for a scatter plot in R
body: <p>I know how to add labels to points in a scatter plot in R using the "text" command, as shown in this question: <a href="https://stackoverflow.com/questions/13229546/how-can-i-label-points-in-this-scatterplot">How can i label points in this scatterplot?</a></p>
  
  <p>But how can I rotate the text lable so that it runs vertically from the point?</p>