Public Release: 

An integrated assessment of vascular plants species of the Americas

Published in Science today

Missouri Botanical Garden

Missouri Botanical Garden researcher Dr. Carmen Ulloa is the lead author of "An Integrated Assessment of Vascular Plant Species of the Americas," published today in Science. Ulloa along with 23 co-authors compiled a comprehensive, searchable checklist of 124,993 species, 6,227 genera and 355 families of vascular plants of the Americas. This represents one third of all known vascular plants worldwide.

Establishing a checklist like this one has long been a goal of the Garden. In 2015, Ulloa started to research what already existed among existing Garden projects and other botanical institutions across the Americas. She then contacted the editors of the 12 major projects in the last 25 years that served as the basis for this larger checklist including the checklists of Bolivia, Brazil, Colombia, Ecuador, the Guianas, Mexico, Peru, the Southern Cone (Argentina, Chile, Paraguay, Uruguay), Venezuela, and the West Indies. Two partially published datasets of the Flora of North America North of Mexico and the Flora Mesoamericana were also used.

The Garden's plant database, Tropicos® was used as the projects data repository for the project. In the process, more than 25,000 names were added to Tropicos before a final list was compiled.

"This is the first time we have a complete overview of the plants of the Americas," said Ulloa. "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. It is vital we have this information so that we know what each species is for conservation purposes."

Co-author Dr. Robert Magill first developed Tropicos in the early 1980s on tiny Osborne 01 microcomputer. Today, it is the world's largest botanical database. It is accessed more 70 million times each year by researchers around the world. It is a link to the past, a digital version of 4.4 million specimens in the Garden's expansive Herbarium. It is also a link to the future, the basis of a larger project, the World Flora Online. The Missouri Botanical Garden and more than 40 other institutions are working to develop the World Flora Online with the goal of documenting all known plant life by 2020.

A number of co-authors are current or former members of the Missouri Botanical Garden research staff including Dr. Gerrit Davidse, Heather Stimmel, Dr. James Zarucchi, Dr. Peter Jørgensen, Magill and Garden President Emeritus Dr. Peter Raven. In addition to this, Dr. Tom Croat and Dr. Charlotte Taylor are both acknowledged in the study's supplemental material for having more than 400 described plant species on the Americas list.

Each year, Missouri Botanical Garden researchers name hundreds of new species of plants with unknown potential. Though the process starts at collection at sites around the world, the real work takes places through the examination and comparison of all known species in Herbaria and in Tropicos. Digital records make it possible for those researchers working around the world to access information on their way to a new discovery. Other recommendations in the paper, including the support and development of taxonomic expertise, more focused research and embrace of new technologies are shared goals of the Garden for its work in around the world.


Digital and video images of a collection of species in this checklist found at the Missouri Botanical Garden can be obtained by emailing

The Missouri Botanical Garden's mission is "to discover and share knowledge about plants and their environment in order to preserve and enrich life." Today, 158 years after opening, the Missouri Botanical Garden is a National Historic Landmark and a center for science, conservation, education and horticultural display.

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