Mosses are second in numbers only to flowering plants. Over the centuries, 50,000 names have been used to describe the 13,000 moss species. In the early 1970's, as the first bryologist on the Garden staff, Crosby took on the challenge of tracking and sorting out these redundancies, and he has become the world's leading authority on moss names.

This taxonomy project, like much of Crosby's work, is decidedly un-showy; he describes the mosses he studies as "little green plants in moist, shady places." But while they may lack the showy appeal of roses or orchids, mosses can be both beautiful and scientifically significant. "Often they are the first plants to appear in areas affected by landslides and lava flows," says Crosby. "Understanding mosses is critical in the big scheme of things."

Crosby delights in working behind the scenes, compiling bibliographies and classifying and preserving the knowledge essential to an understanding of the botanical world. "The value we create for others is to provide a reservoir of information and a standardized base of reference resources," he says. "This is basic science at its best."