The wonders of daisies: the buffet we walk on
A yellow disc with rays of white – an icon of childhood drawings and a flower with healing properties. We have picnics on it, play football on it and make daisy chains out of it.
The common or lawn daisy, Bellis perennis, is probably familiar to most people living in temperate climates. But there may be few things you do not know about this fascinating and perhaps under estimated flower.
A flower made of little flowers
Each daisy is actually an inflorescence – a multitude of tiny flowers called florets working together to set out a buffet for pollinators. There are two types of florets. The tube florets form the yellow centre of the inflorescence, about 100 in a typical daisy. You can see them open in sequence over several days from the outside inwards, revealing their treasures of nectar and pollen.
The ray florets have the long white petals. They are female, whereas each tiny tube floret has a set of male and female floral attributes. Every tube floret produces pollen and nectar as well as having an ovary which can make a tiny fruit at the bottom.
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The white and yellow contrast between the two types of florets is probably attractive to pollinators. Watch a pollinating insect land on a daisy and it will probe each open floret for a sip of nectar. The florets all sit on a capitulum (a cone-shaped platform), which is surrounded by green phyllaries (or bracts). The capitulum also bears the miniature fruits called achenes which are one-seeded fruits.
Unlike some members of the same family, such as the dandelion, the little seeds have no hairy parachute or pappus to help them disperse. This means that most probably drop close to the parent plant, although they can also be dispersed on muddy paws or shoes, and by worms, ants and birds.
Intrepid explorers
The formal name of the daisy – Bellis perennis – was chosen in the 18th century by biologist Carl Linnaeus, who invented the system by which botanists still name species. Bellis is probably from the Latin for beautiful and perennis for perennial or long-lasting. The word daisy is thought to come from “day’s eye”, a reflection of the fact that the flowers close at night.
However, the word daisy is applied to many other species with similar inflorescences and is used to describe a whole family of plants, the Asteraceae. This is the largest family of flowering plants, incorporating species from thistles to sunflowers, almost all of which have the same inflorescence structure of smaller florets collected on a capitulum. There are over 32,000 species in this family, from tiny daisies to large tropical trees. They are found in most ecosystems on earth, except Antarctica.
This indicates they have a successful evolutionary strategy that has allowed them to adapt and spread. The little lawn daisy has travelled around the world from its native distribution in Europe to be ubiquitous in temperate climates from New Zealand to the US.
Circadian strategy
Most flowers stay open all the time but some, like daisies, open towards the sun in the morning to maximise warmth. This may make them more attractive to insect pollinators who need heat to regulate their body temperatures.
The ray florets do the opening and closing, covering the inner disc florets when closed. On cloudy cool days the daisies might not open at all. The movement of the petals is likely to be as a result of cell growth on either side of the long white ligule of the ray floret, with the cells on both sides of the petals growing at different rates.
Resourceful
Gardeners who want the perfect lawn may see daisies as a nuisance. But a 2021 study showed that lawn daisies provided up to 11% of the nectar available to pollinators in some urban environments, making them important food for our urban bees, butterflies, hoverflies and other pollinating insects. These insects are, in turn, food for so many other animals along the food chain.
Daisies can self-pollinate. They can also clone themselves – sending stolons (runners) sideways to colonise a patch of ground. Bellis perennis seems to be well adapted to human-made habitats, with its short sward or dense mat. Daisies with longer swards tend to get outcompeted as they only produce leaves in a rosette near the ground. Its natural habitats include areas of low or disturbed vegetation such as trampled ground, stream edges and lake margins.
Bellis perennis, in common with most flowering plants, forms associations with fungi in its roots. Arbuscular mycorrhizal fungi have been co-evolving with plants for the last 400 million years, allowing the colonisation of land by early plants. The plant feeds the fungi with carbohydrates and in turn, the fungi reach out into the soil and supports the plant with nutrients. This ancient partnership between plants and soil fungi still mediates plant interactions with other soil microbes, and regulates plant-plant interactions.
Human connection
The Asteraceae is probably the most popular plant family in popular medicine containing a wide range of active plant chemicals or phytochemicals with antioxidant, anti-inflamatory, antimicrobial, diuretic and wound-healing properties. Bellis perennis itself has had many common names over the centuries including gardener’s friend, bruisewort and poor-man’s arnica.
It feels like daisies have always been part of our lives in the temperate parts of the world and always will be. Daisies have long featured in literature and poetry, mentioned by Chaucer (The Good Woman), Shakespeare (Ophelia’s flowers in Hamlet) and the 19th century poet John Clare.
But the species that are thriving today are not necessarily assured a future. For example, many once common species of birds, like swifts and skylarks, are in decline now in the UK. Arable weeds such as common corncockle (Agrostemma githago) or cornflower (Centaurea cyanus) that were once a nuisance in crops are now rare species that need intervention to prevent their extinction.
So, we must treasure and monitor these flowers, to ensure they are part of our future as well as our past.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.