Function written in PHP to recursively list all files and directories

/*
Simple directory recursive function
*/
function tree($directory)
{
$mydir=dir($directory);
echo "";
 while($file=$mydir->read()){
if((is_dir("$directory/$file")) AND ($file!=".") AND ($file!=".." )){
echo "$file";
tree("$directory/ $file");
}else{
echo "$file";
}
}
echo "";
$mydir->close();
}
//start the program
echo "The directory is pink";
tree(".");
?>