Dr. Thomas personally collected 173,300 specimens for the herbarium from 1966 until his retirement in 2003. He also collected more than 600,000 duplicate specimens that have been shipped out on exchange programs or to other botanists for further study. This makes Dr. Thomas the most prolific plant collector of all time, far ahead of the second, the famed botanist Julian Steyermark, with 138,000. The Herbarium has exchanged specimens with over 200 different herbaria around the world and Dr. Thomas deposited over 50,000 specimens in the herbaria of the University of Tennessee, the Botanical Research Institute of Texas, the New York Botanical Garden, and the Missouri Botanical Garden, among others. His specialty is the Adders' tongue fern (Ophioglossum), of which he has collected more than everyone else in the world combined. Most of this fascinating collection remains at the ULM herbarium.

After many years of expanding into various rooms of Stubbs Hall, in 2006 the Herbarium moved to a new home on the third floor of Sandel Hall, as part of the consolidated ULM Museum of Natural History. With over 7,500 ft² of floor space of its own, the Herbarium is now easily accessible and in excellent condition for the years to come.

We hope to preserve Dr. Thomas' legacy by developing a plan to image the specimens digitally, geo-reference the collection information, and get this information available online for researchers around the world. More information will be forthcoming.