This collection contains terrestrial plant vouchers collected from select species during plant diversity sampling (NEON sample class: div_voucher_in.voucherSampleID.pla). Plant species diversity is measured once or twice annually in the field. The plot-based method yields plant species data at multiple scales that provide an understanding of changes in composition, distribution, and abundance of native and non-native plant species. The data is comparable within and across NEON sites and to other continental plant diversity efforts to allow for a comprehensive understanding of the impacts of the drivers of change on the diversity of plant species and the functional role they play in ecological systems. A subset of observed plant species is collected and archived. These vouchers are housed at NEON facilities for reference and archived in the NEON Biorepository's herbarium. See related links below for protocols and NEON related data products.