Fewer British fields are bursting into yellow each summer, with 20 percent of native flora species declining at rates that put them at risk of extinction.
The absence of yellow flowers in summer fields is a result of the decline of corn marigold — just one of 345 native British plant species identified as facing the threat of extinction in The Vascular Plant Red Data List published on Monday.
The plant study evaluated the status of every wild plant native to Britain, including commonly found species. Previous threat lists only looked at species already known to be rare.
The widened research scope added 78 species to the threatened list, a 30 percent increase from the last report in 1999.
These included several common flowers previously unknown to be in danger, such as corn buttercup, English eyebright and prickly poppy.
The report rated each species of flower according to the threat they are facing.
The corn marigold is classed as being vulnerable to extinction, while the corn buttercup falls into the more extreme category of critically endangered.
Simon Leach, one of the report's authors and a botanical adviser at English Nature, a government agency that champions the conservation of wildlife, said the decline of some floral species is already visible.
"For those of us with longer memories, it is very evident on a walk through the countryside, that in a sense, the countryside has been drained of much of its flora," Leach said.
Botanists attribute the decline mainly to intensified agricultural practices that use herbicide and fertilizer, increased use of automobiles and over grazing.
Leach said with better management of the countryside the floral abundance of the past could be revived.