by Sheila K. Bennett & Dean B. Bennet

Deep in the wilderness of northern Maine in the mid-1950s, a Harvard PhD student is talking his first steps to map the geology of 300 square miles of Baxter State Park.  Little does he know, he will soon make a major discovery – a small, unique fossil of a plant in a thin layer of black shale.  This discovery of Pertica quadrifaria will help scientists unlock the details of a significant event in the history of our planet – the transition of plants to land, an occurrence that continues to have a critical influence on the Earth’s life-supporting processes, including climate. 

The 400-million-year-old Pertica fossils have been found nowhere else on Earth but that enigmatic rock formation deep in the Maine woods.  Pertica was one of the very first land plants and is thought to have been the tallest of its time.  This fascinating story explores the work of geologists and paleobotanists as they attempt to demystify the land and reveal the ancient life forms that settled on it.  When the Land Turned Green explores the hypothesis that two tall plants (Pertica and white pine) are related and asks: What can these two plants, one ancient and one modern, tell us about the past and perhaps hint at the future?