Researchers from the University of Michigan, as part of an international team of 24, published the first-ever comprehensive list of all known vascular plant species in the Americas. At creation, the searchable database includes 124,993 known species.

Vascular plants are terrestrial species with vascular tissue (known as the xylem) that transport water and minerals throughout the plant. This unique attribute allows vascular plants are able to grow larger than non-vascular plants. Most species, trees and flowering plants included, are vascular.

The project, known as Vascular Plants of the Americas, is led by the Missouri Botanical Garden. It combines decades of research and classification into a single, comprehensive list. 12 existing national and regional lists contributed to the project. The study appeared in Science as “An integrated assessment of the vascular plant species of the Americas.”

Paul Berry, professor in the Department of Ecology and Evolutionary Biology, and curator of vascular plants at the University of Michigan Herbarium and Lois Brako, Assistant Vice President of Research – Regulatory and Compliance Oversight, contributed to the study.

Disocactus martianus, found in Central America/Mexico.

“This is the first time we’ve been able to merge all of this data into a central database—and do a fair amount of data cleanup and verification in the process—to yield an overall picture of all the different native vascular plants found in the Western Hemisphere, based on verified records covering the entirety of the region,” Berry said.

Lead author Carmen Ulloa Ulloa of the Missouri Botanical Garden spoke on the importance of their research. “This is the first time we have a complete overview of the plants of the Americas. It represents not only hundreds of years of plant collecting and botanical research, but 6,164 botanists who described species that appear on this list.”

The nearly 125,000 species are furthered detailed by their families, genera, and geographical foci of their diversity. The list will not remain stagnant for long. Nearly 750 new plant species are discovered each year in the Americas. Researchers expect the database to continue to grow as needed.

Xylem is derived from the Greek zylon meaning ‘wood.’