Accessing super class's hidden fields while using reflection

I will explain it through an example since I am not able to explain the problem.

Let's take 2 classes as below,

public class Vehicle {
    public String series = "Sedan";
}

public class Audi extends Vehicle {
    public String series = "A8";
}

Now, I want to get both the series of Vehicle and Audi. So I can use,

Audi audi = new Audi();
Vehicle vehicle = audi;
String audiSeries = audi.series; //This will give me "A8"
String vehicleSeries = vehicle.series; //This will give me "Sedan"

Here comes my problem: But If I don't have access to Vehicle and Audi classes during compilation and can only use reflection to get the object, how can I get the vehicle's series.

Class audiClass = Class.forName("Audi");
Class vehicleClass = Class.forName("Vehicle");

Object audiObj = audiClass.newInstance();
Field audiSeries = audiClass.getField("series");

System.out.println(audiSeries.get(audiObj));

Output: A8

Is there anyway to get Vehicle class' series field "Sedan" in the above method.

P.S: I cannot change the design to avoid this problem.