"It is a rare plant that grew only in one or two places in Northern California," Smith said, expressing emotion as she spoke of the plant. "They had been warned that it was there... but the road people didn't do it on purpose."

She said the extent of the damage became clear only in recent days when spring budding of new plants began, revealing only five Baker's Delphinium still growing in perhaps the last place in the wild worldwide.

Smith said that some gardeners in Britain may grow the plant, however, and said California researchers had several seeds of the plant as well.