Sexual hormones in Achlya. VII. The hormonal mechanism in homothallic species.

1. A simple membrane technique is described for the study of diffusible sexual hormones in matings on a semisolid medium. 2. Sexual reactions have been shown to occur regularly between mated homothallic species and [male] and [female] strains of heterothallic species. All possible matings between two homothallic species, Achlya americana and Thraustotheca clavata, and [male] and [female] strains of two heterothallic species, A. bisexualis and A. ambisexualis, reveal relationships ranging from no reaction to complete compatibility, and presumably hybridization, between the two mated plants. 3. Matings between the homothallic and heterothallic species listed above, in a semisolid medium in which interposed membranes physically separate the mated plants, prove that the initiation and coordination of the sexual interactions result from diffusible hormones. 4. Assuming similar and interactive sexual hormonal mechanisms in homothallic and heterothallic species, the results of membrane matings confirm exactly th...