diff --git a/doc/git-union-merge.mdwn b/doc/git-union-merge.mdwn
index ac8e8f7a99..0322641efa 100644
--- a/doc/git-union-merge.mdwn
+++ b/doc/git-union-merge.mdwn
@@ -4,12 +4,12 @@ git-union-merge - Join branches together using a union merge
 
 # SYNOPSIS
 
-git union-merge branch ref ref
+git union-merge newref ref ref
 
 # DESCRIPTION
 
 Does a union merge between two refs, storing the result in the
-specified branch.
+specified newref.
 
 The union merge will always succeed, but assumes that files can be merged
 simply by concacenating together lines from all the oldrefs, in any order.
@@ -20,7 +20,7 @@ entirely on git refs and branches.
 
 # EXAMPLE
 
-	git union-merge git-annex git-annex origin/git-annex
+	git union-merge refs/heads/git-annex git-annex origin/git-annex
 
 Merges the current git-annex branch, and a version from origin,
 storing the result in the git-annex branch.
diff --git a/git-union-merge.hs b/git-union-merge.hs
index b0c59a6d36..8e7e0367b7 100644
--- a/git-union-merge.hs
+++ b/git-union-merge.hs
@@ -19,7 +19,7 @@ import qualified GitRepo as Git
 import Utility
 
 header :: String
-header = "Usage: git-union-merge branch ref ref"
+header = "Usage: git-union-merge newref ref ref"
 
 usage :: IO a
 usage = error $ "bad parameters\n\n" ++ header
@@ -109,7 +109,7 @@ commit g branch aref bref = do
 	sha <- getSha "commit-tree" $
 		pipeBoth "git" ["commit-tree", tree, "-p", aref, "-p", bref]
 			"union merge"
-	Git.run g "update-ref" [Param $ "refs/heads/" ++ branch, Param sha]
+	Git.run g "update-ref" [Param branch, Param sha]
 
 {- Runs an action that causes a git subcommand to emit a sha, and strips
    any trailing newline, returning the sha. -}