diff --git a/gtsam/base/VectorSpace.h b/gtsam/base/VectorSpace.h
index 23e314c6b..e1f20ea0c 100644
--- a/gtsam/base/VectorSpace.h
+++ b/gtsam/base/VectorSpace.h
@@ -401,7 +401,8 @@ struct DynamicTraits {
     return result;
   }
 
-  static Dynamic Expmap(const TangentVector& /*v*/, ChartJacobian /*H*/) {
+  static Dynamic Expmap(const TangentVector& /*v*/, ChartJacobian H = boost::none) {
+    static_cast<void>(H);
     throw std::runtime_error("Expmap not defined for dynamic types");
   }