Citrus ichangensis x Poncirus trifoliata (N1tri) seedling
kumquat x C. ichangensis (Ichangquat) seedling
some Yuzu (C. junos) seedlings
Yuzu has a really close genetic relationship with C. ichangensis, it may even be descended from it (possibly as a result of genetric introgression from another C. reticula-like citrus species). Some see Yuzu as a C. ichangensis hybrid (constituting an Ichandarin), although it's certainly not a direct hybrid. Yuzu isn't quite as cold hardy as C. ichangensis, maybe but it is a more vigorous and fast grower and can easily recover from damage. Also the leaves of C. ichangensis smell nothing like Yuzu, although they do share a same distict "deepness". Otherwise the smell of C. ichangensis leaves are very mild (maybe a bit like Kaffir lime leaf) and a bit lemony. The leaves of Yuzu are practically like petitgrain (strong, green, harsh, petitgrain is made from the leaves of bergamot citrus). The fruits of Yuzu are very fragrant though (like a mixture of sour orange, Satsuma mandarin, lemon, and maybe a hint of grapefruit sweetness, and also it is a pungently deep spicy smell).