The iris family survives wildfires by hiding underground in corms and bulbs
Most members of the iris family die back above ground during dry or cold seasons and wait it out as bulbs, corms or rhizomes. In fire-prone grasslands and South African fynbos, that habit is a lifesaver: when flames sweep through in the dry season, the dormant plants sit safely beneath the heat.
Iridaceae contains 69 genera and roughly 2,500 species spread almost worldwide, all perennials with grass-like or sword-shaped leaves folded sharply down the middle. It includes crocuses, freesias and gladioli, and it supplies the spice saffron. The name comes from the genus Iris, coined by Carl Linnaeus in 1753 after the Greek goddess who carried messages from Olympus along a rainbow, whose colours he saw in the petals.
The family's roots are southern. Molecular clock studies suggest it began diverging in Antarctica-Australasia about 82 million years ago. The oldest surviving branch, splitting off some 66 million years ago, is Isophysis, a single Tasmanian species with a star-shaped yellow to brownish flower and the only superior ovary in the family. Southern Africa now holds the greatest variety of genera, and the Crocoideae diversified quickly there as a Mediterranean-style climate took hold.
Iris-family plants have shaped ideas about pollination. Most are pollinated by bees and wasps, often by just one or a few species, and the tight partnerships seen especially in Gladiolus inspired the concept of pollinator syndromes, where flower traits match a particular kind of visitor. Sunbirds and long-tongued flies also pollinate some species. In the Iridoideae, blooms last only briefly, and oil-secreting hairs that attract specialist oil bees have evolved and vanished repeatedly.
Habitats range widely. Gladiolus gueinzii grows on South African shores just above high tide, within reach of sea spray, while the only true shrubs in the family, such as Nivenia and Witsenia, are evergreen. Classification keeps shifting: once grouped with lilies, the family now sits in the order Asparagales, and genetic studies split the old Nivenioideae so that Aristea, Geosiris and Patersonia each became subfamilies of their own.
Source: Iridaceae
