static data in ref classes and in native classes

[rk]

According to the C++ standard, in a native class, a static member
declaration is no definition:

class C {
public:
static int c1;
};

Without a definition like

int C::c1=17;

you get a linker error.

However, ref classes are different:

ref class R {
public:
static int c1;
};

seems to be sufficient, without an extra definition.

Why? I searched the C++/CLI standard and Google, but I found no
indication that ref classes and native classes have to behave different
with respect to static data members.

What did I miss?

Thanks
Richard