Valentines Day is almost upon us, with florists around the world looking forward to bumper sales as men shell out to woo wives and lovers with extravagant floral offerings.
Have flowers evolved specifically to exploit our sense of beauty?
But what is it about flowers which appeals to our emotions?
For hundreds of years, flowers have acted as symbols of human emotions and of love in particular.
The practice of giving flowers reached its height in the Victorian era, when a whole symbolic language of flowers evolved.
But flowers have been used as gifts far longer than that, with evidence that people were presenting each other with bouquets as long ago as 3000 BC.
And pollen deposits found at ancient burial sites dating from 100,000 years ago suggest the practice is even older.
Evolutionary psychologist Dr Dylan Evans, of the University of the West of England, says: "It's extremely ancient. We may have been giving flowers as gifts for almost as long as we've been human.
"It's interesting because there is no fitness benefit to us. How does this help us in the Darwinian struggle for survival?"
Very little research has been carried out into why humans are so attracted to flowers.
A research paper written by another evolutionary psychiatrist, Professor Nicholas Humphrey, in 1973 suggested their appeal might lie in their ability to satisfy the human desire to learn about the world.
Each flower was composed of the same basic elements but they were different enough from each other to help humans start to classify them and learn from them, he argued.
More recently scientists have come up with other hypotheses.
One of these is that our love of flowers is simply learned, that we are taught to like them just as we might be taught to like Shakespeare or Homer or pop music.
But this does not explain why cultures around the world love flowers.
Ancient humans also gave flowers as gifts
Another suggestion is that humans learned to look for flowers because they gave a good indication of where to find fruit.
But the theory which appeals most strongly to Dr Evans is one which puts not the humans but the flowers in the evolutional driving seat.
He says: "Maybe flowers evolved to be beautiful precisely to exploit our sense of beauty in order to help themselves reproduce. They do that with other animals.
"So the question is not why do we find flowers beautiful but how did flowers discover what we found beautiful?
"It seems to be true that that flowers have an immensely powerful effect on human emotions. It's flower power in its most literal sense."
Humans are not the only species attracted to flowers purely for their decorative value.
The bower birds, native to Eastern Australia, are famous for their elaborate decorative nests, which the males build and then decorate with flowers, chewed up berries and charcoal for the females to inspect.
Dr Evans says: "They build the most incredible displays and then the females inspect them and when it comes to choosing a mate they choose the best artist.
"And they've been doing this for millions of years before humans were even around."