Iridaceae

 ( Asparagales Families ) 

Members of the subfamilies Crocoideae and Nivenioideae first began cladogenesis in arid conditions in Africa, accelerating for Crocoideae as the Mediterranean climate emerged in Southern Africa. A similar process occurred for the tribe Tigridieae in Iridoideae following long-distance Seed dispersal from South to North America, resulting in high levels of endemism. In the tribe Sisyrinchieae, the continued formation of the Andes supported the movement to lower elevations along the Atlantic Ocean.

The aerial portions of deciduous species die back when the bulb or corm enters dormancy. The plants thus survive periods that are unfavorable for growth by retreating underground. This is particularly useful in grasslands and fynbos, which are adapted to regular burning in the dry season. At this time the plants are dormant and their bulbs or corms are able to survive the heat of the fires underground. Veld fires clear the soil surface of competing vegetation, as well as fertilize it with ash. With the arrival of the first rains, the dormant corms are ready to burst into growth, sending up flowers and stems before they can be shaded out by other vegetation. Many grassland and fynbos irids flower best after fires and some fynbos species will only flower in the season after a fire.

The majority of Iridaceae are Pollination by Hymenoptera, frequently by single species or a small group of species. These tight relationships found in individual species of Iridaceae, especially in Gladiolus, were the inspiration for the description of pollinator syndromes. Pollinators include various species of solitary bees, as well as , Nemestrinidae (such as Moegistorhynchus longirostris), Butterfly, and night . Ancestrally, flowers were zygomorphic, as in Crocoideae, with contrasting Floral nectary locations for pollinators. Flowers may present nectar and pollen rewards to visitors, but some genera may only offer nectar such as in Gladiolus and Watsonia. Species of Ferraria produce putrid smells, floral cups, and dark mottled perianth in order to attract Diptera. Members of Iridoideae and Nivenioideae have radially symmetric trumpet-like flowers that secrete large amounts of nectar. This novel morphology enabled additional floral complexity and rapid evolution of pollinator relationships, as frequently as a new relationship over 5 speciations. New World Iridoideae represent one of the largest offering oil to pollinators, ranging from forced pollination using hinged petals to frequent failure to pollinate. Most of the variability in flowers occurs between subfamilies, including inflorescence structure, i.e. rhipidia, panicle, or spike, and floral longevity, i.e. less than one day to five days. Some members of the tribe Irideae have flowers functioning as meranthia, or developing as three separate zygomorphic units that pollinators visit individually.