For decades, hybridizers have crossed the diploid regelia species, I. korolkowii, with various diploid onco species to obtain hybrids that combine the best traits of the two groups. The result is a class of arils with exotic flowers on plants that are relatively easy to grow.

Andromache, 1915

Charon, 1907

Luna, 1908

I. korolkowii x I. barnumae mariae

I. korolkowii venosa x I. atropurpurea

I. korolkowii violacea x I. susiana

Theseus, bef. 1952

Parentage Unknown

Yes, the number after the name is the year it was introduced (although in the case of the unregistered 'Theseus' it's just the earliest listing I was able to find). As a group, these are usually described as having limited fertility, but all of these have contributed significantly to our modern gene pool.