diff --git a/docs/reference.html b/docs/reference.html
index 2696279..7e8c10e 100644
--- a/docs/reference.html
+++ b/docs/reference.html
@@ -201,7 +201,7 @@ <h2>modification</h2>
             (see <code>.graft</code> for details).</p>
           <div class="desc">Adds nodes and edges to the current set in the particle system and removes
             any that are not present in the new branch. Conserved nodes will maintain their position
-            and state.
+            and state. Note that nodes must be listed if they are to be conserved, not inferred from edges.
             </div>
             <hr>
         </dd>