diff --git a/tree.go b/tree.go
index b616d0f..8851e54 100644
--- a/tree.go
+++ b/tree.go
@@ -17,7 +17,6 @@ var (
 const (
 	paramPrefix     = "{"
 	paramSuffix     = "}"
-	plusParamPrefix = paramPrefix + "+"
 	starParamPrefix = paramPrefix + "*"
 )