Embryology and breeding systems in Crocus (Iridaceae)--a study in causes of chromosome variation

A detailed description of female reproductive structures in Crocus is given, using three different techniques: wax embedding and sectioning, SEM, and observation of cleared ovules by interference contrast microscopy. The results of this examination, and a chromosomal investigation of the intraspecific hybrids obtained by crossing specimens of C. speciosus of different karyotypes, are used to test the hypothesis that Crocus is apomictic. Although facultative diplospory cannot be entirely ruled out, it is suggested that apomixis is an unlikely explanation from the unusual amount of chromosomal variation found in some species of Crocus, and alternative causes are discussed.