Crocus roots can drag their own bulb deeper into the ground
A crocus grows from a corm, and special contractile roots pull that corm downward to the right depth, sometimes as far as 20 centimetres. Its flower stalk stays underground too, only stretching upward once seeds ripen. One autumn species, Crocus sativus, gives the world saffron, among the costliest spices there is.
The genus holds about 100 species of perennials in the iris family, native from the Mediterranean and North Africa through central Europe, the Middle East and Central Asia as far as Xinjiang in western China. They grow low, bloom in white, yellow, orange or purple in autumn, winter or spring, close up at night and in dull weather, and go dormant after flowering. Crocuses reached Europe from Turkey in the 16th century and caught on as garden ornaments.
Saffron is the dried stigma of Crocus sativus, prized as spice and dye, with Iran at the centre of production. Its colour comes from crocins, water-soluble yellow pigments found in the plant's floral tissue. Laboratory work continues on saffron's compounds, including a review of their antioxidant effects on male fertility that concluded clinical relevance remains uncertain without better human trials.
The plant has a long written history. Theophrastus described it in the fourth century BC, the Romans brought saffron crocus to Britain as a dye plant, and Crusaders reintroduced it to Western Europe. In 1548 William Turner treated crocus and saffron as the same word, suggesting the English knew only the saffron species; by 1597 John Gerard described eleven forms, and in 1656 John Parkinson listed 27 spring and 4 autumn kinds while noting only one was true saffron.
Classifying crocuses has been messy. Linnaeus formally named the genus in 1753 but lumped a spring and an autumn species together as mere varieties, and filed a plant from another genus under it. George Maw's 1886 monograph became the basis of modern understanding. The chromosomes are notoriously unruly, with counts from 6 to 70 recorded, sometimes within a single species, and botanists often tell species apart by the corm's outer coat rather than the leaves, which barely vary.
Source: Crocus
