diff --git a/src/kernel/terrain.h b/src/kernel/terrain.h
index 945d07794..931a74861 100644
--- a/src/kernel/terrain.h
+++ b/src/kernel/terrain.h
@@ -64,7 +64,7 @@ extern "C" {
         short max_road;             /* this many stones make a full road */
         short distribution;         /* multiplier used for seeding */
         struct terrain_production *production;
-        const struct item_type **herbs;     /* zero-terminated array of herbs */
+        struct item_type **herbs;     /* zero-terminated array of herbs */
         const char *(*name) (const struct region * r);
         struct terrain_type *next;
     } terrain_type;