Riley Black’s new book, When the Earth was Green, uses the latest research to envision the ancient worlds of our favorite prehistoric animals.

The Smithsonian Institution in the 1850s recruited hundreds of citizen scientists across the nation to track when they saw plants bud or grow leaves. At the time, Florida had been a state for only six ...

THIS little book meets a real want ... and reasoning upon problems connected with variation. Variation in Animals and Plants. By H. M. Vernon The International Scientific Series.