diff --git a/src/pydiverse/transform/core/ops/dtypes.py b/src/pydiverse/transform/core/ops/dtypes.py
index f39047a..c4a3ecd 100644
--- a/src/pydiverse/transform/core/ops/dtypes.py
+++ b/src/pydiverse/transform/core/ops/dtypes.py
@@ -68,7 +68,7 @@ class Float(DType):
 
 
 class String(DType):
-    name = "float"
+    name = "str"
 
 
 class Bool(DType):
diff --git a/src/pydiverse/transform/core/ops/registry.py b/src/pydiverse/transform/core/ops/registry.py
index 96339e4..ba7b7ad 100644
--- a/src/pydiverse/transform/core/ops/registry.py
+++ b/src/pydiverse/transform/core/ops/registry.py
@@ -4,6 +4,7 @@
 import functools
 import inspect
 import itertools
+import textwrap
 import typing
 from functools import partial
 
@@ -381,6 +382,14 @@ class TrieNode:
         operator: OperatorImpl | None
         children: list[OperatorImplementationStore.TrieNode]
 
+        def __repr__(self):
+            self_text = f"({self.value} - {self.operator})"
+            if self.children:
+                children_text = "\n".join(repr(c) for c in self.children)
+                children_text = textwrap.indent(children_text, "  ")
+                return self_text + "\n" + children_text
+            return self_text
+
     def __init__(self, operator: Operator):
         self.operator = operator
         self.root = self.TrieNode("ROOT", None, [])