To many, cannabis is a recreational drug; to some, it is a medicine. Now, it is increasingly seen as a crop, to be grown in quantity and engineered for better traits—not just pharmacological effects, but also fiber content and the rapid, efficient growth that makes a plant useful for biofuels. This month, in a special issue of Critical Reviews in Plant Sciences, researchers delve into all aspects of cannabis biology and ecology. The work sheds light on how the plant has diversified since it was first grown 8500 years ago in Eurasia.

In 2008, Brazilian researchers embarked on a major effort to develop a comprehensive list of the nation's plants by 2010, the deadline for the goals set forth in the 1992 Convention on Biological Diversity, an international treaty on the conservation of flora and fauna worldwide.

Microbes aside, upward of nine in 10 species crowd into the 30% of Earth's surface that's dry. It wasn't always that way, say a pair of researchers at the University of California (UC), Davis, who have been studying land and ocean features to understand how evolution proceeds in these two realms.

If one gene is good, more genes are better. That's the mantra of plant biologists working to improve crops. Already, companies have engineered varieties that carry both herbicide and insect resistant genes.

A computer whiz turned geneticist borrows tactics from Wal-Mart and cattle breeders to manage what may be the world's largest genetic analysis.

Researchers probe the secrets of how plants cope with water stress to improve crop yields.

The sequencing of maize genomes and the development of new strains are enabling faster exploitation of this key crop's natural diversity.

The nation of Ethiopia is seeking to leverage its past-including its most famous daughter, the hominid called Lucy-to help secure its future.