Chinese flower has evolved to be less visible to pickers

Fritillaria delavayi, used in traditional medicine, turning grey to blend into rocks

For thousands of years, the dainty Fritillaria delavayi has grown slowly on the rocky slopes of the Hengduan mountains in China, producing a bright green flower after its fifth year.

But the conspicuous small plant has one deadly enemy: people, who harvest the flower for traditional Chinese medicine.