The saffron crocus, unknown in the wild, likely descends from Crocus cartwrightianus, which originated in Crete; C. thomasii and C. pallasii are other possible precursors. The saffron crocus is a triploid that is "self-incompatible" and male sterile; it undergoes aberrant meiosis and is hence incapable of independent sexual reproduction—all propagation is by vegetative multiplication via manual "divide-and-set" of a starter clone or by interspecific hybridisation. If C. sativus is a mutant form of C. cartwrightianus, then it may have emerged via plant breeding, which would have selected for elongated stigmas, in late Bronze Age Crete. Saffron's taste and iodoform- or hay-like fragrance result from the chemicals picrocrocin and safranal. It also contains a carotenoid dye, crocin, which imparts a rich golden-yellow hue to dishes and textiles.
DescriptionEditThe domesticated saffron crocus, Crocus sativus, is an autumn-flowering perennial plant unknown in the wild. Its progenitors are possibly the eastern Mediterranean autumn-flowering Crocus cartwrightianus, which is also known as "wild saffron" and originated in Greece. The saffron crocus likely resulted when C. cartwrightianus was subjected to extensive artificial selection by growers seeking longer stigmas. C. thomasii and C. pallasii are other possible sources.
It is a sterile triploid form, which means that three homologous sets of chromosomes compose each specimen's genetic complement; C. sativus bears eight chromosomal bodies per set, making for 24 in total. Being sterile, the purple flowers of C. sativus fail to produce viable seeds; reproduction hinges on human assistance: corms, underground, bulb-like, starch-storing organs, must be dug up, broken apart, and replanted. A corm survives for one season, producing via this vegetative division up to ten "cormlets" that can grow into new plants in the next season. The compact corms are small, brown globules that can measure as large as 5 cm (2.0 in) in diameter, have a flat base, and are shrouded in a dense mat of parallel fibres; this coat is referred to as the "corm tunic". Corms also bear vertical fibres, thin and net-like, that grow up to 5 cm above the plant's neck.