diff --git a/environment.rst b/environment.rst
index 337ee15..ac6ed03 100644
--- a/environment.rst
+++ b/environment.rst
@@ -240,6 +240,6 @@ only two sample values possible, 1 represents minimum intensity
 depth and frame type combinations, a sample value of 0 represents
 minimum intensity and larger values represent increasing intensity.
 
-The combination of bit depth 1 and :macro:`SANE_FRAME_RGB (or
+The combination of bit depth 1 and :macro:`SANE_FRAME_RGB` (or
 :macro:`SANE_FRAME_RED`, :macro:`SANE_FRAME_GREEN`, :macro:`SANE_FRAME_BLUE`)
 is rarely used and may not be supported by every frontend.