Mallards and their domesticated conspecifics are also fully interfertile. Both the wild pears are interfertile with domesticated pears. Further, all the species were interfertile. All citrus trees belong to the single genus "Citrus" and remain almost entirely interfertile. All the subspecies, varieties, and cultivars are conspecific and interfertile. All the subspecies, varieties, and cultivars are interfertile. Further, both are completely interfertile, while "L. discoidea" is restricted to serpentine habitats.