diff --git a/git-merge-recursive.py b/git-merge-recursive.py
index e599b11cc57ecd0219d39fbfc8141fa5455755bf..b7fb0961e0758c566c459f51b6983f99e694ee4f 100755
--- a/git-merge-recursive.py
+++ b/git-merge-recursive.py
@@ -98,7 +98,7 @@ def merge(h1, h2, branch1Name, branch2Name, graph, callDepth=0):
 def getFilesAndDirs(tree):
     files = Set()
     dirs = Set()
-    out = runProgram(['git-ls-tree', '-r', '-z', tree])
+    out = runProgram(['git-ls-tree', '-r', '-z', '-t', tree])
     for l in out.split('\0'):
         m = getFilesRE.match(l)
         if m: