Three types of F1 plants occur in crosses between O. lamarckiana and O. rubricalyx: velans h latifrons with a ring of 8 chromosomes and 3 pairs, in which bud color is independent of the velans lethal and the ring; gaudens [center dot] h latifrons with the same configuration, in which bud color is completely linked to the gaudens lethal and the ring; and gaudens [center dot] modified-velans with a ring of 12 and a pair, in which bud color is linked to the velans and gaudens lethals and to the ring. The velans lethal and the gene for bud color are in different chromosomes but show complete linkage when both chromosomes are in a common ring.