diff --git a/meshmode/discretization/connection/direct.py b/meshmode/discretization/connection/direct.py
index 2dfffc4e..ffbad9b3 100644
--- a/meshmode/discretization/connection/direct.py
+++ b/meshmode/discretization/connection/direct.py
@@ -596,7 +596,10 @@ def __call__(
 
         # {{{ recurse into array containers
 
-        if not isinstance(ary, DOFArray):
+        from numbers import Number
+        if isinstance(ary, Number):
+            return ary
+        elif not isinstance(ary, DOFArray):
             try:
                 iterable = serialize_container(ary)
             except NotAnArrayContainerError: