Our new geologic era requires modern approaches for preventing extinction events. Previous work on plant extinctions in the United States and Canada discovered that 64% were single-site endemics (Knapp et al. 2021). This agrees with a recent global analysis of plant extinctions that showed taxa from one area/or with extremely limited geographic ranges are the most common trait shared for all extinct plants (Humphreys et al. 2020).  Current methodologies used by the International Union for the Conservation of Nature (IUCN) and NatureServe do not explicitly identify or prioritize taxa of One Known Occurrence (OKO) for conservation action. NatureServe has assessed the entire flora of the United States and Canada. Of these assessments, ca. 1250 taxa are given the highest assessment rank, G1 - Critically Imperiled with Extinction. Given the lack of funding available for plant conservation, it is obvious additional prioritizations are needed to meaningly prevent extinctions. In situ and ex situ conservation methods should be employed for all OKO plants if such actions haven’t already occurred. The Endangered Species Act (ESA) is the mechanism for the protection of plants under Federal law. There is a common misconception that such extremely rare organisms must already be protected under the ESA, but that is not correct. In one case, the U.S. Fish and Wildlife Service was petitioned to list an OKO, but the petition was eventually denied. We will present our preliminary findings on the OKO plants in the USA and Canada. In partnership with the Laukahi Network, we are also conducting a parallel analysis for Hawai’i.