What is the equivalent of the "is" operator for reflected generic types?

Using the is operator in C# with generic types is straightforward:

if (new List<MyClass>()) is IEnumerable<MyClass>) {
    // always branches
}

But what about when comparing types? I was hopeful that I could use Type.IsSubclassOf(Type type) here, but System.Collections.Generic.List<> implements System.Collections.Generic.IEnumerable<> -- It doesn't extend it. So I assume that's why the following happens:

var listType = typeof(List<MyClass>);
var enumerableType = typeof(IEnumerable<MyClass>);

if (listType.IsSubclassOf(enumerableType)) {
    // NEVER branches
}

If I had an instance of my rvalue Type I could easily use Type.IsInstanceOfType(object o), but this point in the code is far removed from the instance from which the Type in question was reflected.

Am I missing something in the Type API? Am I forced to roll my own via an extension method?