Gene flow between species of different ploidy levels is important in plant evolution and breeding. A cytological study was conducted on a natural population with individuals belonging to the diploid L. purpurea Gay (2n= 10) and to the tetraploid L. coquimbensis F. Phil (2n= 18) species, as well as intermediate phenotypes of apparent hybrid origin. The genus Leucocoryne is endemic to Chile and it exhibits heterogeneity, presumably genetic, for shape, size, and color of its flowers. The objective of the study was to determine if there is gene flow between species having different ploidy levels. From the karyotypic analyses of the seeds, only parental types having 2n= 10 and 2n= 18 individuals were observed. However, from the bulb analyses, 2n= 10, 2n= 18, 2n= 14, and 2n= 22 individuals were encountered. The karyotypes of the 2n= 14 and 2n= 22 individuals suggest the occurrence of natural interespecific hybridization between species with different ploidy levels in nature. Models which may account for the origin of these genotypes are proposed.

Received for publication 26 Apr. 2004. Accepted for publication 20 May 2004. We thank Drs. R. Craig and C. Quiros for their valuable suggestions to improve the manuscript and Mr. Luis Arriagada for his assistance in collecting. This research was supported with funds from Fondo-SAG of the Servicio Agrícola y Ganadero, Chile.