Index: wp-admin/css/dashboard.css
===================================================================
--- wp-admin/css/dashboard.css	(revision 31928)
+++ wp-admin/css/dashboard.css	(working copy)
@@ -1103,6 +1103,11 @@
 		padding: 5px;
 	}
 
+	/* Hide "Dismiss" Text */
+	.welcome-panel .welcome-panel-close {
+		font-size: 0;
+	}
+
 	/* Make the close icon larger for tappability. */
 	#welcome-panel.welcome-panel .welcome-panel-close:before {
 		font-size: 20px;