diff --git a/src/core/ReactComponent.js b/src/core/ReactComponent.js
index e59c37fd69..85bf82115f 100644
--- a/src/core/ReactComponent.js
+++ b/src/core/ReactComponent.js
@@ -296,7 +296,7 @@ var ReactComponent = {
           if (child.length === 0) continue;
 
           if (targetArray === null) targetArray = [];
-          appendNestedChildren(i - 1, child, targetArray);
+          appendNestedChildren('' + (i - 1), child, targetArray);
 
         } else if (!isEmptyChild(child)) {
 
diff --git a/src/core/__tests__/ReactIdentity-test.js b/src/core/__tests__/ReactIdentity-test.js
index 8e00f1ebb0..71614082b9 100644
--- a/src/core/__tests__/ReactIdentity-test.js
+++ b/src/core/__tests__/ReactIdentity-test.js
@@ -53,8 +53,8 @@ describe('ReactIdentity', function() {
     React.renderComponent(instance, document.createElement('div'));
     var node = instance.getDOMNode();
     reactComponentExpect(instance).toBeDOMComponentWithChildCount(2);
-    checkId(node.childNodes[0], '.reactRoot[0].:0:first');
-    checkId(node.childNodes[1], '.reactRoot[0].:0:second');
+    checkId(node.childNodes[0], '.reactRoot[0].[0]{first}');
+    checkId(node.childNodes[1], '.reactRoot[0].[0]{second}');
   });
 
   it('should allow key property to express identity', function() {
@@ -67,8 +67,8 @@ describe('ReactIdentity', function() {
     React.renderComponent(instance, document.createElement('div'));
     var node = instance.getDOMNode();
     reactComponentExpect(instance).toBeDOMComponentWithChildCount(2);
-    checkId(node.childNodes[0], '.reactRoot[0].:apple');
-    checkId(node.childNodes[1], '.reactRoot[0].:banana');
+    checkId(node.childNodes[0], '.reactRoot[0].[apple]');
+    checkId(node.childNodes[1], '.reactRoot[0].[banana]');
   });
 
   it('should use instance identity', function() {
@@ -89,12 +89,12 @@ describe('ReactIdentity', function() {
     React.renderComponent(instance, document.createElement('div'));
     var node = instance.getDOMNode();
     reactComponentExpect(instance).toBeDOMComponentWithChildCount(3);
-    checkId(node.childNodes[0], '.reactRoot[0].:wrap1');
-    checkId(node.childNodes[0].firstChild, '.reactRoot[0].:wrap1.:squirrel');
-    checkId(node.childNodes[1], '.reactRoot[0].:wrap2');
-    checkId(node.childNodes[1].firstChild, '.reactRoot[0].:wrap2.:bunny');
-    checkId(node.childNodes[2], '.reactRoot[0].:2');
-    checkId(node.childNodes[2].firstChild, '.reactRoot[0].:2.:chipmunk');
+    checkId(node.childNodes[0], '.reactRoot[0].[wrap1]');
+    checkId(node.childNodes[0].firstChild, '.reactRoot[0].[wrap1].[squirrel]');
+    checkId(node.childNodes[1], '.reactRoot[0].[wrap2]');
+    checkId(node.childNodes[1].firstChild, '.reactRoot[0].[wrap2].[bunny]');
+    checkId(node.childNodes[2], '.reactRoot[0].[2]');
+    checkId(node.childNodes[2].firstChild, '.reactRoot[0].[2].[chipmunk]');
   });
 
   it('should let restructured components retain their uniqueness', function() {
diff --git a/src/core/__tests__/ReactMultiChildReconcile-test.js b/src/core/__tests__/ReactMultiChildReconcile-test.js
index bead6ae660..597ca8f182 100644
--- a/src/core/__tests__/ReactMultiChildReconcile-test.js
+++ b/src/core/__tests__/ReactMultiChildReconcile-test.js
@@ -42,10 +42,11 @@ var stripEmptyValues = function(obj) {
 
 /**
  * These children are wrapped in an array and therefore their keys are prefixed.
- * This relies on a tiny implementation detail of the rendering system.
+ * Their name is also wrapped in an prefix and suffix character. We strip those
+ * out. This relies on a tiny implementation detail of the rendering system.
  */
 var getOriginalKey = function(childName) {
-  return childName.substr(3);
+  return childName.substr(4, childName.length - 5);
 };
 
 /**
diff --git a/src/utils/__tests__/mapChildren-test.js b/src/utils/__tests__/mapChildren-test.js
index 7933e0c211..32ac55bdb6 100644
--- a/src/utils/__tests__/mapChildren-test.js
+++ b/src/utils/__tests__/mapChildren-test.js
@@ -122,10 +122,10 @@ describe('mapChildren', function() {
       .instance();
 
     expect(mapFn.calls.length).toBe(3);
-    expect(mapFn).toHaveBeenCalledWith(kidOne, 'one', 0);
-    expect(mapFn).toHaveBeenCalledWith(kidTwo, 'two', 1);
-    expect(mapFn).toHaveBeenCalledWith(kidThree, 'three', 2);
+    expect(mapFn).toHaveBeenCalledWith(kidOne, '0:one', 0);
+    expect(mapFn).toHaveBeenCalledWith(kidTwo, '0:two', 1);
+    expect(mapFn).toHaveBeenCalledWith(kidThree, '0:three', 2);
     expect(rendered.props.children).not.toEqual(instance.props.children);
-    expect(rendered.props.children).toHaveKeys(['one', 'two', 'three']);
+    expect(rendered.props.children).toHaveKeys(['0:one', '0:two', '0:three']);
   });
 });
diff --git a/src/utils/flattenChildren.js b/src/utils/flattenChildren.js
index 031b86e588..2728220b19 100644
--- a/src/utils/flattenChildren.js
+++ b/src/utils/flattenChildren.js
@@ -56,7 +56,7 @@ var flattenChildrenImpl = function(res, children, nameSoFar) {
       flattenChildrenImpl(
         res,
         child,
-        nameSoFar + ':' + escapedKey
+        nameSoFar + '[' + escapedKey + ']'
       );
     }
   } else {
@@ -80,7 +80,7 @@ var flattenChildrenImpl = function(res, children, nameSoFar) {
             flattenChildrenImpl(
               res,
               children[key],
-              nameSoFar + ':' + escapedKey
+              nameSoFar + '{' + escapedKey + '}'
             );
           }
         }