diff --git a/ls.1 b/ls.1
index ec34925..e3220bc 100644
--- a/ls.1
+++ b/ls.1
@@ -43,7 +43,9 @@ Append a file type indicator to directories.
 .It Fl q
 Replace non-printable characters in filenames with '?'.
 .It Fl R
-List directory content recursively.
+List directory content recursively.  The
+.Fl 1
+flag is set implicitly.
 .It Fl r
 Reverse the sort order.
 .It Fl t