The plant is an iridacea and belongs to the Crocus genus of which about 80 species are part. The adult plant consists of a bulb-tuber of a diameter of about 5 cm. The bulb contains about 20 undifferentiated gems from which all the plant's organs originate, but in general only 3 are the main buds that will give rise to the flowers and leaves, while the others, smaller, will produce only secondary bulbs. During the vegetative development from the main buds of the bulb the jets develop, one for each bud; therefore from each bulb about 2 or 3 will sprout. The jets sprout from the ground wrapped in a white and hard protective cuticle, which allows the plant to pierce the crust of the soil.
The jet contains the leaves and the almost completely developed flowers, once it has come out of the ground, it opens and allows the leaves to lengthen and the flower to open completely.
The saffron flower is a perigonium formed by 6 petals of intense violet color. The male part is made up of 3 yellow anthers on which the pollen is placed. The female part is formed by the ovary, stylus and stigmas. From the ovary, located at the base of the bulb, a long yellow-colored stylus originates which, after covering the whole jet, reaches the base of the flower, here it is divided into 3 long, bright red stigmas.
The leaves of the Crocus sativus are very narrow and elongated. Generally they reach the length of 30–35 cm, while they never exceed the width of 5 mm.
Crocus sativus is a sterile triploid plant, it is the result of an intensive artificial selection of a species native to the island of Crete, the Crocus cartwrightianus. A selection implemented by growers who tried to improve stigma production. Its genetic structure makes it incapable of generating fertile seeds, which is why its reproduction is only possible by cloning the mother bulb and its diffusion is closely linked to human assistance.