UK and US botanists to tame notorious ‘evil tribe’ of ironweeds with $1.2 million NSF and NERC award

The National Science Foundation (NSF) and Natural Environment Research Council (NERC) have awarded botanists at Fort Worth Botanic Garden | Botanical Research Institute of Texas (FWBG | BRIT) and the Royal Botanic Gardens, Kew (RBG Kew) $1.2 million (nearly $850,000 from NSF and nearly £300,000 from NERC) to classify and understand plants in a hyper-diverse group referred to as "ironweeds" in the sunflower family, Asteraceae (also known as Compositae). This is the first grant of its kind awarded to FWBG | BRIT and RBG Kew through a special international collaborative program between NSF and NERC.

This group of plants forms what plant taxonomists refer to as the Vernonieae tribe and includes approximately 1,500 species of herbs, shrubs, trees and vines worldwide. The "ironweeds" have confounded botanists attempting to understand patterns shared by species in this group, which has led experts to describe Vernonieae by a notorious nickname: the "evil tribe."

Morgan Gostel, FWBG | BRIT Research Botanist and Principal Investigator (PI), said: "Vernonieae is incredibly confusing. The characteristics among many species overlap and vary to a degree that it's hard to differentiate them as distinct genera. At the same time, other plants in the tribe are highly distinctive with little in common and are quite easy to recognize and distinguish at the taxonomic level of genus. For most of the history of Vernonieae, more than one thousand species were classified in the same genus (Vernonia), but Vernonia has been reduced to just 20 species. This has left the remaining species of this once vast genus in a state of limbo or 'purgatory' until taxonomists determine their correct placement."

Recently, considerable research in the Americas has begun to unravel the mysteries of the tribe and species formerly placed in the genus Vernonia; however, nearly half of the species of Vernonieae are restricted to the Eastern Hemisphere and have been long neglected by botanists, according to Gostel. Funding from this NSF-NERC award will allow the researchers to reclassify diversity in Vernonieae from the Eastern Hemisphere and develop tools to help others identify and understand this enigmatic group of plants. Members of the team at RBG Kew include Dr. Isabel Larridon, Dr. Benoit Loeuille and Dr. Ana Rita Simões.

Dr. Isabel Larridon, Kew Research Leader and co-PI for the grant, said: "Taxonomic knowledge like this is essential to conserving the diversity of plant life on the planet. Understanding the diversity of the nearly half-a-million plant species on Earth is a strategic priority for Kew Science. Yet there are too many plant species and not enough trained taxonomists to study, describe and distribute information about them."

While resolving questions about Vernonieae, Gostel and Larridon will also advance the distribution of scientific information and the training of the next generation of scientists by working with at least three graduate students and four undergraduate students. Further international training will be provided through workshops with students, botanists, and herbarium and university staff, as well as via environmental programmes offered by FWBG | BRIT and RBG Kew.

The results of their work will be added to the newly established Global Compositae Database (GCD), a public online taxonomic resource for the sunflower family. The GCD, coordinated by the International Compositae Alliance (TICA) is part of a global effort to develop an online database of all plant life and is recognized as a Taxonomic Expert Network by the World Flora Online.

During the four-year project, Gostel, Larridon and their team will conduct fieldwork in five countries critical to sampling for this work (the Democratic Republic of the Congo, Madagascar, Mozambique, South Africa and Thailand) and study plant specimens in numerous herbaria around the world, most notably at RBG Kew, FWBG | BRIT, Missouri Botanical Garden, Muséum National d'Histoire Naturelle in Paris, and Botanic Garden Meise. They will analyse the DNA of Vernonieae and the morphological features such as small hairs, pollen and flowers from these plant species to identify patterns that can help them classify diversity in the group.

Gostel said: "By better understanding Vernonieae, we will be making great strides in understanding the complexity of this group and making important discoveries that will help botanists understand and communicate about plant diversity in other groups. We expect the 'evil tribe' won't be so evil when we're done."

Provided by Royal Botanic Gardens, Kew