Iridaceae is a family of plants in order Asparagales, taking its name from the irises, meaning rainbow, referring to its many colours. There are 66 accepted genera with a total of c. 2244 species worldwide (Christenhusz & Byng 2016[2]). It includes a number of other well known cultivated plants, such as freesias, gladioli and crocuses.
Members of this family are perennial plants, with a bulb, corm or rhizome. The plants grow erect, and have leaves that are generally grass-like, with a sharp central fold. Some examples of members of this family are the blue flag and yellow flag.
The family name is based on the genus Iris, the largest and best known genus in Europe. This genus dates from 1753, when it was coined by Swedish botanist, Carl Linnaeus. Its name derives from the Greek goddess, Iris, who carried messages from Olympus to earth along a rainbow, whose colours were seen by Linnaeus in the multi-hued petals of many of the species.
The family is currently divided into four subfamilies but the results from DNA analysis suggest that several more should be recognised:
Subfamily Crocoideae is one of the major subfamilies in the family Iridaceae. It contains many genera, including Afrocrocus, Babiana, Chasmanthe, Crocosmia, Crocus, Cyanixia, Devia, Dierama, Duthieastrum, Freesia, Geissorhiza, Gladiolus, Hesperantha, Ixia, Lapeirousia, Melasphaerula, Micranthus, Pillansia, Romulea, Sparaxis, Savannosiphon, Syringodea, Thereianthus, Tritonia, Tritoniopsis, Xenoscapa and Watsonia. They are mainly from Africa, but includes members from Europe and Asia. The rootstock is usually a corm, they have blooms which sometimes have scent are collected in inflorescence and contain six tepals. The nectar is produced mostly in the base of the bloom from the glands of the ovary, which is where the flower forms a tube-like end. In some species there is no such end and the plant only provides pollen to pollinating insects. Members of this subfamily have the sword-shaped leaves typical of Iridaceae.
Subfamily Isophysidoideae contains the single genus Isophysis, from Tasmania. It is the only member of the family with a superior ovary and has a star-like yellow to brownish flower.