European Bellis perennis (the scientific name means 'perennial beauty') is one of the commonest plants of close-cropped grassland in the British Isles, whether it is rabbit-grazed coastal turf or an urban lawn. On a summer's day, the change of a green lawn to one blotched with white within a few hours of dawn is a familiar sight. The transformation is due to the diurnal opening of the flower heads of the common daisy, whose name is derived from the Old English daeges eage ('day's eye).
The flower heads (capitula) with their ring of white ray florets and central yellow tube florets are a delight to many people from mid March until mid-October. Some flowering individuals are likely to be found even in the middle of winter.
Pollinators are attracted to flowers by chemical and structural features. One of these structural features may the interaction of light with regularly arranged, microscopic surface features. The ray florets of Bellis perennis have distinct microscopic furrows produced by cylindrical, transversely-striated cells. Under laboratory conditions these surface features produce diffraction patterns which may attract insect pollinators. However, under natural light conditions these effects are lost, indicating that such features are unlikely to attract the natural pollinators of Bellis. In Bellis, pollinators are likely to be attracted by the contrast between the capitulum's ray and tube florets.
The common daisy has been a recurrent feature of English literature since at least the fourteenth century; Geoffrey Chaucer described the common daisy as 'the emperice, and floure of floures alle'. In Scotland, Robert Burns reflected on the daisy's fate under a plough shear and the brevity of our lives: 'Full on thy bloom, Till crush'd beneath the furrow's weight'. Daisy-chain construction opened one of the most well-known stories in children's literature, Lewis Carroll's Alice's Adventures in Wonderland (1865). Repetition and symmetry make daisy-chain analogies commonplace in fields as diverse as computing, crocheting, transplant surgery and angling.
Wherever Europeans have settled in temperate regions of the world, e.g., the Americas and Australasia, Bellis perennis has become naturalised. Often such long-distance transportation of common daisies are inadvertent, the fruits perhaps caught in mud on the sole of a boot or in animal fodder. However, the common daisy has also attracted the attention of gardeners because of the myriad of colour variants and capitulum forms which are found in nature. Many of these have been selected to produce prized garden plants.
van der Kooi CJ et al 2014. Iridescent flowers? Contribution of surface structures to optical signaling. New Phytologist 203: 667-673.