Index: boost/graph/distributed/named_graph.hpp
===================================================================
--- boost/graph/distributed/named_graph.hpp	(revision 78218)
+++ boost/graph/distributed/named_graph.hpp	(working copy)
@@ -1199,11 +1199,12 @@
   typedef typename Config::distribution_type distribution_type;
   typedef typename Config::base_distribution_type base_distribution_type;
 
-  explicit maybe_named_graph(const process_group_type&)  { }
+  explicit maybe_named_graph(const process_group_type& pg)
+    : pg(pg) { }
 
   maybe_named_graph(const process_group_type& pg, 
                     const base_distribution_type& distribution) 
-    : distribution_(pg, distribution) { }
+    : pg(pg), distribution_(pg, distribution) { }
 
   /// Notify the named_graph that we have added the given vertex. This
   /// is a no-op.