cosmetics/typos
diff --git a/Doc/libfuncs.tex b/Doc/libfuncs.tex
index f276fb2..ed2427b 100644
--- a/Doc/libfuncs.tex
+++ b/Doc/libfuncs.tex
@@ -233,7 +233,7 @@
   expression.
 \end{funcdesc}
 
-\begin{funcdesc}{open}{filename\, \optional{mode\optional{\, bufsize}}}
+\begin{funcdesc}{open}{filename\optional{\, mode\optional{\, bufsize}}}
   Return a new file object (described earlier under Built-in Types).
   The first two arguments are the same as for \code{stdio}'s
   \code{fopen()}: \var{filename} is the file name to be opened,