diff --git a/src/dendropy/dataio/nexusprocessing.py b/src/dendropy/dataio/nexusprocessing.py
index 3d1fb8c2..a2f9edbc 100644
--- a/src/dendropy/dataio/nexusprocessing.py
+++ b/src/dendropy/dataio/nexusprocessing.py
@@ -480,9 +480,9 @@ def escape_nexus_token(label, preserve_spaces=False, quote_underscores=True):
         return ""
     if not preserve_spaces \
             and "_" not in label \
-            and not re.search(r'''[\(\)\[\]\{\}\\/\\,\\;\\:\\=\\*'"\`\+\-\<\>\0\t\n]''', label):
+            and not re.search(r'''[()[\]{}\\\/,;:=*'"`+\-<>\\0\\t\\n]''', label):
         label = label.replace(' ', '_').replace('\t', '_')
-    elif re.search(r'''[\(\)\[\]\{\}\\/\,\;\:\=\*'"\`\+\-\<\>\0\t\n\r ]''', label) \
+    elif re.search(r'''[()[\]{}\\\/,;:=*'"`+-<>\0\t\n\r ]''', label) \
         or quote_underscores and "_" in label:
         s = label.split("'")
         if len(s) == 1: