George L. Goodale, who became the first director of the Harvard Botanical Museum in 1888, analyzes plants in a laboratory in the Harvard University Herbaria.

Asa Gray and Louis Agassiz started out as friends.

The two frequented the same natural history societies, spoke at the same popular Boston lecture series, and dined together at the Faculty Club in their early days as Harvard professors in the 1840s.

They worked just blocks from each other on campus, pioneering separate institutions that would shape Harvard for generations to come. But in 1859, a revolutionary idea sprouted across the pond—and irrevocably drove them apart.

When Charles Darwin published “On the Origin of Species,” Agassiz staunchly resisted the British scientist’s controversial theory—Gray, however, became one of Darwin’s most ardent proponents in America.

Their diverging opinions influenced the trajectories of each naturalist’s burgeoning project: Gray’s botanical haven on Garden Street sowed the seeds of Harvard’s evolution-oriented herbaria, while Agassiz designed the Museum of Comparative Zoology on Oxford Street with a non-evolutionary viewpoint in mind.

Both institutions have survived and thrived. But while the MCZ is a popular afternoon destination for families toting small children, the herbaria are frequented mainly by researchers. Gray’s role in enduring Harvard traditions—including the Harvard Summer School, which he founded 140 years ago—has faded from popular memory.

But a project digitizing Darwin’s letters has helped draw Gray and the herbaria back into the limelight.

“We think of [Gray] as being a quiet old botanist,” says history of science professor Janet Browne, the general editor of the U.S. branch of the Darwin Correspondence Project. “But actually, he was a tremendous intellectual and activist in getting these ideas out and about.”

Those ideas he espoused bear fruit to this day in the Harvard University Herbaria, where scientists glean new knowledge from centuries-old specimens.

NATURAL RESOURCES

Gray’s herbarium, which relocated from Garden Street to Divinity Avenue in 1954, is today joined by four more Harvard herbaria that together house more than five million specimens—as well as state-of-the-art labs for analyzing them.

In addition, the copious historical documents stored in the herbaria’s libraries are pored over by botanists from institutions all over the world, as well as many historians of science.

Donald H. Pfister, the interim director of the Harvard University Herbaria, oversees the preservation and distribution of all these specimens. His office is a testament to the riches quietly accumulated over the years at the herbaria. A hat made of mushrooms, an enormous framed stamp featuring Gray’s visage (created for the bicentennial anniversary of his birth last year), and field guides with ornate covers all adorn his shelves. Pfister says that not only plants, but also personalities live on in the herbaria.

“We’ve all left little pieces of ourselves in the collections,” he says. “We’ve annotated, made notes, written labels. The ghosts are there, in a way.”

To this day, artist-scientists spend their days drying, mounting, and labeling new additions. In the mounting room, soothing music fills the air, and the tables are strewn with historic newspapers in which specimens were once wrapped. The team has been busy salvaging about 13,000 specimens that were damaged in a flood two years ago, a task which is now nearly complete.