diff --git a/includes/token.inc b/includes/token.inc
index c31f9e6..63481f7 100644
--- a/includes/token.inc
+++ b/includes/token.inc
@@ -17,7 +17,7 @@
  *
  * Tokens follow the form: [$type:$name], where $type is a general class of
  * tokens like 'node', 'user', or 'comment' and $name is the name of a given
- * placeholder. For example, [node:title].
+ * placeholder. For example, [node:title] or [node:created:since].
  *
  * In addition to raw text containing placeholders, modules may pass in an array
  * of objects to be used when performing the replacement. The objects should be
@@ -103,9 +103,16 @@ function token_replace($text, array $data = array(), array $options = array()) {
  *   An associative array of discovered tokens, grouped by type.
  */
 function token_scan($text) {
-  // Matches tokens with the following pattern: [$type:$token]
-  // $type and $token may not contain white spaces.
-  preg_match_all('/\[([^\s\]:]*):([^\s\]]*)\]/', $text, $matches);
+  // Matches tokens with the following pattern: [$type:$name]
+  // $type and $name may not contain  [ ] or whitespace characters.
+  // $type may not contain : characters, but $name may.
+  preg_match_all('/
+    \[             # [ - pattern start
+    ([^\s\[\]:]*)  # match $type not containing whitespace : [ or ]
+    :              # : - separator
+    ([^\s\[\]]*)   # match $name not containing whitespace [ or ]
+    \]             # ] - pattern end
+    /x', $text, $matches);
 
   $types = $matches[1];
   $tokens = $matches[2];
diff --git a/modules/system/system.test b/modules/system/system.test
index 3045569..60f5d2c 100644
--- a/modules/system/system.test
+++ b/modules/system/system.test
@@ -1577,9 +1577,10 @@ class TokenReplaceTestCase extends DrupalWebTestCase {
     $result = token_replace($source, array('node' => $node), array('language' => $language, 'clear' => TRUE));
     $result = $this->assertFalse(strcmp($target, $result), 'Valid tokens replaced while invalid tokens cleared out.');
 
-    // Test without using the clear parameter (non-existant token untouched).
+    // Test without using the clear parameter (non-existent token untouched).
     $target .= '[user:name]';
     $target .= '[bogus:token]';
+
     $result = token_replace($source, array('node' => $node), array('language' => $language));
     $this->assertFalse(strcmp($target, $result), 'Valid tokens replaced while invalid tokens ignored.');
 
@@ -1596,6 +1597,35 @@ class TokenReplaceTestCase extends DrupalWebTestCase {
   }
 
   /**
+   * Test whether token-replacement works in various contexts.
+   */
+  function testSystemTokenRecognition() {
+    global $language;
+    $source = $target = '';
+
+    // Generate prefixes and suffixes for the token context.
+    $tests = array(
+      array('prefix' => 'this is the ', 'suffix' => ' site'),
+      array('prefix' => 'this is the', 'suffix' => 'site'),
+      array('prefix' => '[', 'suffix' => ']'),
+      array('prefix' => '', 'suffix' => ']]]'),
+      array('prefix' => '[[[', 'suffix' => ''),
+      array('prefix' => ':[:', 'suffix' => '--]'),
+      array('prefix' => '-[-', 'suffix' => ':]:'),
+      array('prefix' => '[:', 'suffix' => ']'),
+      array('prefix' => '[site:', 'suffix' => ':name]'),
+      array('prefix' => '[site:', 'suffix' => ']'),
+    );
+    foreach ($tests as $test) {
+      $source .= $test['prefix'] . '[site:name]' . $test['suffix'];
+      $target .= $test['prefix'] . 'Drupal' . $test['suffix'];
+    }
+
+    $result = token_replace($source, array(), array('language' => $language));
+    $this->assertFalse(strcmp($target, $result), 'Token recognized within a string context.');
+  }
+
+  /**
    * Tests the generation of all system site information tokens.
    */
   function testSystemSiteTokenReplacement() {