diff --git a/demo/index.html b/demo/index.html
index 616c84f..e33ce5e 100644
--- a/demo/index.html
+++ b/demo/index.html
@@ -364,7 +364,6 @@ <h2>Chart gallery</h2>
 
   <google-chart
     type="sankey"
-    options='{"title": "Distribution of days in 2001H1"}'
     cols='[{"label": "From", "type": "string"},
            {"label": "To", "type": "string"},
            {"label": "Weight", "type": "number"}]'
@@ -444,6 +443,31 @@ <h2>Chart gallery</h2>
     }());
   </script>
 
+  <p>Here's a wordtree:</p>
+
+  <google-chart
+      type="wordtree"
+      data='[["Phrases"],
+             ["cats are better than dogs"],
+             ["cats eat kibble"],
+             ["cats are better than hamsters"],
+             ["cats are awesome"],
+             ["cats are people too"],
+             ["cats eat mice"],
+             ["cats meowing"],
+             ["cats in the cradle"],
+             ["cats eat mice"],
+             ["cats in the cradle lyrics"],
+             ["cats eat kibble"],
+             ["cats for adoption"],
+             ["cats are family"],
+             ["cats eat mice"],
+             ["cats are better than kittens"],
+             ["cats are evil"],
+             ["cats are weird"],
+             ["cats eat mice"]
+          ]'></google-chart>
+
   <p>Here are three gauges:</p>
 
   <google-chart
diff --git a/google-chart-loader.html b/google-chart-loader.html
index f7382a2..22a526e 100644
--- a/google-chart-loader.html
+++ b/google-chart-loader.html
@@ -9,6 +9,12 @@
   /** @type {string} Most charts use this package. */
   var DEFACTO_CHART_PACKAGE = 'corechart';
 
+  /** @enum {string} Namespaces that contain chart constructors. */
+  var Namespace = {
+    CHARTS: 'charts',
+    VIS: 'visualization'
+  };
+
   /**
    * A collection of chart type details.
    *
@@ -28,6 +34,10 @@
     'bubble': {
       ctor: 'BubbleChart',
     },
+    'calendar': {
+      ctor: 'Calendar',
+      pkg: 'calendar',
+    },
     'candlestick': {
       ctor: 'CandlestickChart',
     },
@@ -37,6 +47,10 @@
     'combo': {
       ctor: 'ComboChart',
     },
+    'gauge': {
+      ctor: 'Gauge',
+      pkg: 'gauge',
+    },
     'geo': {
       ctor: 'GeoChart',
     },
@@ -79,27 +93,24 @@
       ctor: 'Timeline',
       pkg: 'timeline',
     },
-    'gauge': {
-      ctor: 'Gauge',
-      pkg: 'gauge',
-    },
     'treemap': {
       ctor: 'TreeMap',
       pkg: 'treemap',
     },
-    'calendar': {
-      ctor: 'Calendar',
-      pkg: 'calendar',
+    'wordtree': {
+      ctor: 'WordTree',
+      namespace: Namespace.VIS,
+      pkg: 'wordtree',
     }
   };
 
   /**
-   * Returns the namespace for the given chart type.
+   * The Google Charts constructor namespace inferred from the given chart type.
    * @param {string} type the type of the chart
    * @return {!Object} the namespace that contains the chart's constructor
    */
   function namespaceForType(type) {
-    return google[type.indexOf('md-') === 0 ? 'charts' : 'visualization'];
+    return google[type.indexOf('md-') === 0 ? Namespace.CHARTS : Namespace.VIS];
   }
 
   /** @type {!Object<string, boolean>} set-like object of gviz packages to load */
@@ -216,7 +227,8 @@
       }
       return this._loadPackages([chartData.pkg || DEFACTO_CHART_PACKAGE])
         .then(function() {
-          return namespaceForType(type)[chartData.ctor];
+          var namespace = google[chartData.namespace] || namespaceForType(type);
+          return namespace[chartData.ctor];
         });
     },
 
diff --git a/google-chart.html b/google-chart.html
index 3538617..0f1f6f3 100644
--- a/google-chart.html
+++ b/google-chart.html
@@ -111,6 +111,7 @@
        * - `table`
        * - `timeline`
        * - `treemap`
+       * - `wordtree`
        *
        * See <a href="https://google-developers.appspot.com/chart/interactive/docs/gallery">Google Visualization API reference (Chart Gallery)</a>
        * for details.