diff --git a/core/boot.js b/core/boot.js
index 7ebe32eab..4d07a67e7 100644
--- a/core/boot.js
+++ b/core/boot.js
@@ -445,14 +445,16 @@ $tw.modules.applyMethods = function(moduleType,targetObject) {
 };
 
 /*
-Return an array of subclasses created from the modules of a specified type
+Return an array of classes created from the modules of a specified type. Each module should export the properties to be added to those of the optional base class
 */
-$tw.modules.createSubclassesFromModules = function(moduleType,baseClass) {
+$tw.modules.createClassesFromModules = function(moduleType,baseClass) {
 	var classes = {};
 	$tw.modules.forEachModuleOfType(moduleType,function(title,moduleExports) {
 		var newClass = function() {};
-		newClass.prototype = new baseClass();
-		newClass.prototype.constructor = baseClass;
+		if(baseClass) {
+			newClass.prototype = new baseClass();
+			newClass.prototype.constructor = baseClass;
+		}
 		$tw.utils.extend(newClass.prototype,moduleExports);
 		classes[moduleExports.name] = newClass;
 	});
diff --git a/core/modules/wikivocabulary.js b/core/modules/wikivocabulary.js
index 127ec3278..198793b00 100644
--- a/core/modules/wikivocabulary.js
+++ b/core/modules/wikivocabulary.js
@@ -13,9 +13,9 @@ module-type: global
 var WikiVocabulary = function(options) {
 	this.wiki = options.wiki;
 	// Hashmaps of the various parse rule classes
-	this.pragmaRuleClasses = $tw.modules.createSubclassesFromModules("wikipragmarule",$tw.WikiRule);
-	this.blockRuleClasses = $tw.modules.createSubclassesFromModules("wikiblockrule",$tw.WikiRule);
-	this.runRuleClasses = $tw.modules.createSubclassesFromModules("wikirunrule",$tw.WikiRule);
+	this.pragmaRuleClasses = $tw.modules.createClassesFromModules("wikipragmarule",$tw.WikiRule);
+	this.blockRuleClasses = $tw.modules.createClassesFromModules("wikiblockrule",$tw.WikiRule);
+	this.runRuleClasses = $tw.modules.createClassesFromModules("wikirunrule",$tw.WikiRule);
 	// Hashmap of the various renderer classes
 	this.rendererClasses = $tw.modules.applyMethods("wikirenderer");
 	// Hashmap of the available widgets