diff --git a/lib/spack/spack/environment.py b/lib/spack/spack/environment.py
index a919ee5ceeb..ab02f46222f 100644
--- a/lib/spack/spack/environment.py
+++ b/lib/spack/spack/environment.py
@@ -1574,7 +1574,7 @@ def matching_spec(self, spec):
                             if abstract)
 
         if len(root_matches) == 1:
-            return list(root_matches.items())[0][1]
+            return list(root_matches.items())[0][0]
 
         # More than one spec matched, and either multiple roots matched or
         # none of the matches were roots