the smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound. 2. Chemistry.
The cultivated saffron (saffron crocus C. sativus) flowers in the autumn and comes up every year, so it is known as a perennial plant. It does not grow wild, and is now a triploid form of the eastern Mediterranean plant called Crocus cartwrightianus. It is thought that C. cartwrightianus came from Crete.he cultivated saffron (saffron crocus C. sativus) flowers in the autumn and comes up every year, so it is known as a perennial plant. It does not grow wild, and is now a triploid form of the eastern Mediterranean plant called Crocus cartwrightianus. It is thought that C. cartwrightianus came from Crete.
Assuming that you are referring to the common hibiscus, Hibiscus rosa-sinensis, they are perennials, because they are viable year after year. Annuals are plants that grow, flower, and die in the space of one year. Of course, hibiscus are also tropical plants, so if you grow them in a northern area (where winter temps fall below freezing,) they will be killed by the cold, so you will have to get new bushes every year - thus, you might think they are annuals.