1 files changed, 9 insertions, 2 deletions
diff --git a/sys/libbio/phylo.c b/sys/libbio/phylo.c
index 8033e35..374cd08 100644
--- a/sys/libbio/phylo.c
+++ b/sys/libbio/phylo.c
@@ -6,9 +6,15 @@ error
 phylo·addchild(bio·Node* parent, bio·Node* child)
 {
     bio·Node *it, *sibling;
-    if (parent->nchild < 2) {
+    switch (parent->nchild) {
+    case 1:
+        parent->child[0]->sibling = child;
+    case 0:
         parent->child[parent->nchild++] = child;
-    } else {
+    break;
+
+    default:
+        sibling = parent->child[1];
         for (it = parent->child[1]->sibling; it != nil; it = it->sibling) {
             sibling = it;
         }
@@ -16,5 +22,6 @@ phylo·addchild(bio·Node* parent, bio·Node* child)
         parent->nchild++;
     }
 
+    child->parent = parent;
     return 0;
 }