Meiosis and sporogenesis in a haploid plant of Pellaea glabella var. occidentalis

In spore mother cells of a sporophyte of Pellaea glabella var. occidentalis (E. Nelson) Butters resulting from induced apogamy, the chromosomes did not pair during prophase I and separated randomly, usually into two groups. Meiosis II generally produced tetrads with nuclei of unequal sizes. Spore walls began to form around these nuclei, but most of the spores eventually aborted. One apparently normal spore, which later germinated, is assumed to have resulted from the formation of a restitution nucleus at the end of meiosis I.The total lack of pairing among the 29 chromosomes of this plant is evidence that this number represents the basic haploid complement of the species.