According to recent DNA studies, the closest relatives of Iris (Pardanthopsis) dichotoma and Iris domestica (AKA Belamcanda chinensis) are probably the bearded irises (including both eupogons and arils.)

Thank You very much can they cross with lilies also .

As mentioned above, these are the plants from crossing Pardanthopsis(formerly Iris) dichotoma and Iris domestica (formerly Belamcanda chinensis). These parent plants are commonly called 'Vesper Iris' and 'Blackberry Lily' respectively. It is unfortunate in my mind that almost all of the plants available have nearly totally lost the iris form and only resemble more vigorous and colorful blackberry lilies. In my opinion, a profitable goal would be back-crossing again to the vesper iris to regain some of this form with the vigor and sunny colors of the blackberry lily.

The chronosome count of these plants does not match any other common member of the iris group, so out-crossing would be highly unlikely to succeed.

George

Right George. And they are in different sections from the more common iris species. Inter-sectional crosses are generally dificult in the genus Iris.
And I have thought about backcrossing to vesper iris. This is the only plant in the iris genus that, for me, can sprout in the spring and bloom by fall. Annual iris. But they are perennial also, at least in mild winters here.