Seed structure in Crocus sativus L. ×, C. cartwrightianus Herb., C. thomasii Ten., and C. hadriaticus Herb. at SEM

Crocus sativus L. (Iridaceae) is a sterile triploid geophyte widely cultivated for the production of the spice saffron and only reproduced by means of corms. Extensive research has identified Crocus cartwrightianus Herb. as being a probable progenitor of C. sativus. However, other diploid Crocus species of the same C. sativus group, such as C. thomasii Ten. and C. hadriaticus Herb., have been considered as possible progenitors of saffron. Of the characteristics for distinguishing critical genera, species and intraspecific taxa of angiosperms, the most widely adopted have been seed organisation and patterns of spermoderma microstructure detected at SEM. The aim of this study is to use SEM to analyse the seeds of C. sativus ×, a cross obtained by C. sativus with pollen of C. cartwrightianus Herb. and the seeds of allopollinated C. cartwrightianus, C. thomasii Ten., and C. hadriaticus Herb. Results indicate that the seed surface microstructure of C. sativus × is very similar to that of C. cartwrightianus while being different from those of C. thomasii and C. hadriaticus.