C++ virtual function: Base class function is called instead of derived

I have following code snippet:

using namespace std;
class base
{
    public:
    virtual void print(char a){ std::cout<<" Base "<<std::endl;}
};
class derived :public base
{
    public:
    void print(floata)  {std::cout<<" Derived "<<std::endl;}
};

int main()
{
    base* d = new derived;
    d->print(1.5);

    return 0;
}

Output is "base" Why output is coming from base function and not from derived one