Studies on the Mechanism of Parthenogenesis

In this work parthenogenesis is thus defined, in accordance with WINKLER and ROSENBERG, as the process by means of which an azygoid (haploid) or a zygoid (diploid) egy-cell is produced and then develops without any fusion of nuclei nnd cells.WINKLER makes a distinction between generative and somatic parthenogenesis.But as these partial terms may suggest the idea that a purely somatic process is the cause of the origin of the egg-cell having the zygoid number, we shall employ here, as in the case of animals, the terms azygoid and zygoid parthenogenesis (v. for instance PRELL, 1923, and ANKEL, 1929).The expressions haploid and diploid parthenogenesis used by many investigators are not employed either, owing to the dual meaning of the terms haploid and diploid.For the rarely occurring instances of synergid, antipode or polar nuclear embryos in the phanerogams WINKLER employs the term STHASBURGER'S (1909) and ERNST'S (1918).