diff --git a/arrow/arrow.py b/arrow/arrow.py
index 3837ae362..42e1dff52 100644
--- a/arrow/arrow.py
+++ b/arrow/arrow.py
@@ -302,7 +302,7 @@ def range(cls, frame, start, end=None, tz=None, limit=None):
         iterating.  As such, either call with naive objects and ``tz``, or aware objects from the
         same timezone and no ``tz``.
 
-        Supported frame values: year, quarter, month, week, day, hour, minute, second.
+        Supported frame values: year, quarter, month, week, day, hour, minute, second, microsecond.
 
         Recognized datetime expressions:
 
@@ -378,7 +378,7 @@ def span_range(cls, frame, start, end, tz=None, limit=None, bounds="[)"):
         iterating.  As such, either call with naive objects and ``tz``, or aware objects from the
         same timezone and no ``tz``.
 
-        Supported frame values: year, quarter, month, week, day, hour, minute, second.
+        Supported frame values: year, quarter, month, week, day, hour, minute, second, microsecond.
 
         Recognized datetime expressions:
 
@@ -424,7 +424,7 @@ def interval(cls, frame, start, end, interval=1, tz=None, bounds="[)"):
             the start, '[' includes the start, ')' excludes the end, and ']' includes the end.
             If the bounds are not specified, the default bound '[)' is used.
 
-        Supported frame values: year, quarter, month, week, day, hour, minute, second
+        Supported frame values: year, quarter, month, week, day, hour, minute, second, microsecond.
 
         Recognized datetime expressions:
 
@@ -447,7 +447,7 @@ def interval(cls, frame, start, end, interval=1, tz=None, bounds="[)"):
             ...
             (<Arrow [2013-05-05T12:00:00+00:00]>, <Arrow [2013-05-05T13:59:59.999999+00:00]>)
             (<Arrow [2013-05-05T14:00:00+00:00]>, <Arrow [2013-05-05T15:59:59.999999+00:00]>)
-            (<Arrow [2013-05-05T16:00:00+00:00]>, <Arrow [2013-05-05T17:59:59.999999+00:0]>)
+            (<Arrow [2013-05-05T16:00:00+00:00]>, <Arrow [2013-05-05T17:59:59.999999+00:00]>)
         """
         if interval < 1:
             raise ValueError("interval has to be a positive integer")
@@ -750,7 +750,7 @@ def span(self, frame, count=1, bounds="[)"):
             the start, '[' includes the start, ')' excludes the end, and ']' includes the end.
             If the bounds are not specified, the default bound '[)' is used.
 
-        Supported frame values: year, quarter, month, week, day, hour, minute, second.
+        Supported frame values: year, quarter, month, week, day, hour, minute, second, microsecond.
 
         Usage::