Plant status designations of the Pennsylvania Natural Heritage Program include a category of Tentatively Undetermined (TU) for plants believed to be in danger of population decline but which cannot presently be included within another classification due to insufficient data. Plants classified as TU do not receive protection under the Pennsylvania Wild Plant Conservation Act,nor do they trigger environmental review. Using a combination of field surveys and herbarium research we gathered data to support proposed status changes for five species currently listed as TU to Pennsylvania Endangered (PE), Pennsylvania Threatened (PT), or Pennsylvania extirpated (PX). In addition, we evaluated current and historical records for ten additional TU species for which information remains ambiguous and no clear status recommendations can be made at this time. These recommendations were reviewed by the Rare Plant Forum and the Vascular Plants Technical Committee on April 24, 2010. Recommended changes will be incorporated in the revised regulations now under development by DCNR Bureau of Forestry.