The Genetics of Self-Incompatibility in Oenothera Organensis.

ENOTHERA organensis is endemic to the Organ Mountains of 0 southern New Mexico where the entire population apparently consists of considerably less than one thousand individuak2 The morphology of the seeds indicates a relationship to members of the subgenus Oenothera (sometimes called Onagra), but the growth habit and ovule placentation resemble types belonging to the subgenus Raimannia (the Euoenothera of Engler and Prantl). Oenothera organensis has proved completely cross-sterile with five species of Raimannia. Hybrids with Oenothera species are obtained infrequently, and are almost completely sterile, resembling Oenothera-Raimannia hybrids. Oenothera organensis differs from both these subgenera in being completely self-sterile. The inheritance of self-incompatibilty in Oe. organensis proved to be of the Nicotiana type, governed by a series of multiple allelomorphs. Interest attaches not so much to the mode of inheritance as to the methods by which genetic analyses can be followed in this material.