[R] mtext: rotating text

[Jonathan Dushoff]

Recently, I was trying to make an inward-facing label for a vertical
axis on the right-hand side of a plot.  The inward-facing label was
required by a journal.  I searched R-help, but the only solution I found
was to use text, which requires fiddling with the x-coordinate for each
plot.  What would have been perfect is a way to rotate text in mtext.

I had a similar problem trying to use mtext to put a vertical label on a
vertical axis with horizontal tick labels.  

Jonathan Dushoff