Botanic gardens and arboreta are a vibrant part of the natural history collections community, serving society in areas such as education, recreation, and research. Unfortunately, at the present time dwindling support and advocacy for collections-based research has placed these institutions in the midst of a collections crisis. In this review, I assess the historical importance of living plant collections in supporting research, examine why their research potential is currently unmet, and provide a series of rationales in support of collections-based research. To avert this crisis several things must occur, the most basic of which is stronger advocacy for living collections and the research derived from them. Traditional views of collections management need to be evaluated under new light and the pool of researchers expanded. Formal, on-site programs are not required for collections to be used for research, as off-site scientists can make great contributions. Toward this end, collaborative links between the garden and research communities ought to be enhanced through the pivotal role played by curators and collections managers. Investment in data-management systems are also required to increase collection value and improve the ability to disseminate information to researchers who require it. If provided the necessary leadership and support, living plant collections have great potential to meet future scientific needs.

Xeric limestone prairies (XLPs) are open, nonforested areas in which herbaceous plant communities occur on shallow, rocky soils derived from calcareous substrates. These grasslands are characterized by dominance of C₄ perennial grasses (particularly Schizachyrium scoparium) and are distributed in eastern United States from Missouri and Pennsylvania south to Arkansas and Georgia. XLPs occur in the Ozark Plateaus, Central Lowland, Interior Low Plateaus, Appalachian Plateaus, Ridge and Valley, and Coastal Plain physiographic provinces, and they are developed on Alfisols, Ultisols, Mollisols, Inceptisols, and Vertisols derived from Paleozoic limestones (also Eocene), dolomites, and calcareous shales. The C₄ perennial prairie grass S. scoparium is the characteristic dominant taxon in XLPs of eastern United States. However, C₃ perennial forbs are dominant in some sites, and C₄ annual grasses (Sporobolus spp.) may be locally dominant in shallow-soil-zone microsites. Thirteen taxa apparently are endemic, or nearly so, to this vegetation type, including eight in the Ridge and Valley in Alabama (Cahaba River valley), four in the Ozark Plateaus in Missouri and Arkansas, and one in the Ridge and Valley of West Virginia and Virginia. Various types of information are used to construct a conceptual model of the origin, maintenance, and successional dynamics of XLPs. Affinities of XLPs in eastern United States to other herbaceous vegetation types in eastern and western North America are discussed, and directions for future research are suggested.