The Impatiens hawkeri Bull. x I. platypetala Lindl. hybrid 7851-1 was studied for characteristics of unreduced pollen.When I. hawkeri x platypetah 785 1-1 (2n = 24) was crossed as a pollen parent to I. hawkeri x aurantiaca Tangeglow (2n = 24), offspring contained somatic chromosome numbers ranging from 2n = 30 to 2n = 36. In root-tip cells of each of these offspring, there were 4 I. aurantiara chromosomes, as expected after normal meiosis of the seed parent Tangeglow. This result showed that unreduced pollen was contributed by 7851-1. Additionally, a study of 7851-1 micropores showed that, at the tetrad stage, 76 'X o f cello w.xe dyads, and microspores forming from dyads of 7851-1 were noticeably larger than microspores forming the tetrads. An examination of pollen meiosis in 7851-1 showed that the meiotic mechanism for unreduced pollen formation was parallel spindles in the second meiotic division. As a seed parent, 7851-1 was sterile both in crosses and by self pollination. As a pollen parent, 7851-1 was successfully crossed only to seed parents containing I. uutwztiucu chromosomes, indicating that I . auvuntiacu is a bridging species in interspecific crosses involving I. haivkeri and I. plutypetala. The implications for breeding New Guinea Imputiens (I. huwkeri) cultivars using interspecific hybridization are discussed.