1. Meiosis of haploid forms ofAntirrhinum majus L. (n = 8) is characterized by an extremely high degree of pairing between inhomologous or partially homologous chromosomes. In extreme cases this pairing leads to the formation of four bivalents. Besides bivalents trivalents and more complex pairing configurations were found in pachytene. Fold-backs of whole chromosomes or of chromosome segments occurred in a considerable number of PMC. Pairing within the haploid chromosome set took place in most cases between inhomologous chromosome segments, but in later stages of first meiotic division it was possible to show the existence of at least one intrachromosomal and one interchromosomal duplication. The interchromosomal duplication causes preferential pairing of two specific chromosomes. 2. In diakinesis and meta-anaphase I pairing — configurations consisting of two or more chromosomes were found. According to form and valence of these configurations it was possible to establish with certain reservations a minimal chiasma frequency of 0.8 per PMC. One part (40%) of chiasmata is probably formed between the segments of the interchromosomal duplication. The other 60% are either chiasmata between further duplications, which cannot be demonstrated cytologically, or chiasmata between inhomologous segments. The possibility is not excluded that part of these configurations are not held together by chiasmata, but are pseudoconfigurations caused by matrix stickiness. 3. The various PMC-types are grouped according to the different combinations of uni-, bi- and multivalents found in them. 42,34% of the analyzed PMC contained 8 univalents, 39,82% one bivalent, 11,94% two bivalents, 2,14% three bivalents, 0,27% four bivalents. The last 3,49% of PMC were characterized by trivalents and a few higher associations. 4. The abnormal second meiotic division was analyzed in order to find out the way of origin of the various types of sporades containing one to eight microspores. Dividing univalents in first meiotic division, the type of distribution of univalents to the poles, the formation of restitution nuclei and abnormal cytokinesis were found to be responsible for the development of the different types of sporades. The haploid plants were practically self-sterile but by pollination with diploid forms some progeny could be raised. 5. Form, extent and consequences of inhomologous pairing are discussed. It is supposed that there is a general pairing tendency of unknown nature in meiotic prophase which will be saturated by preferential contact between homologous chromosomes. The existence of homologous partners is supposed to prevent pairing of inhomologous chromosomes. But if there are only inhomologous chromosomes within one nucleus the general pairing tendency in meiotic prophase leads to associations of inhomologous chromosomes. The existence of homologous segments within one set of mostly inhomologous chromosomes causes preferential pairing of these identical regions, but does not suppress inhomologous pairing.