How does JsonUtility.FromJson() handle Inheritance?

How do I read json with inherited types to the proper sub types?

 public class JsonTest : MonoBehaviour  
 {  
     void Start ()  
     {  
         Base b = new Base() { id = 1, name = "Bob" };  
         Sub s = new Sub() { id = 2, name = "Builder", age = 5, number = 123.345f };  
 
         string sB = JsonUtility.ToJson(b);  
         string sS = JsonUtility.ToJson(s);  
         Debug.LogFormat("{0}\n{1}", b, s);  
         Debug.LogFormat("{0}\n{1}", sB, sS);  
         Debug.LogFormat("{0}\n{1}", JsonUtility.FromJson<Base>(sB), JsonUtility.FromJson<Base>(sS));  
     }  
 }
 
 [Serializable]  
 public class Base  
 {  
     public long id;  
     public string name;  
 
     public override string ToString()  
     {  
         return String.Format("[id:{0}, name:{1}]", id, name);  
     }  
 }  
 
 [Serializable]  
 public class Sub : Base  
 {  
     public int age;  
     public float number;  
 
     public override string ToString()  
     {  
         return String.Format("[id:{0}, name:{1}, age:{2}, number:{3}]", id, name, age, number);  
     }  
 }  

Output

• ToString() -- Works as expected
  [id:1, name:Bob]
  [id:2, name:Builder, age:5, number:123.345]

• JsonUtility.ToJson() -- works as expected
  {"id":1,"name":"Bob"}
  {"id":2,"name":"Builder","age":5,"number":123.34500122070313}

• JsonUtility.FromJson() -- doesn't deserialize sub types
  [id:1, name:Bob]
  [id:2, name:Builder]

Is there any way to do this?