| Vascular plant extinction in the continental United States and Canada WM Knapp, A Frances, R Noss, RFC Naczi, A Weakley, GD Gann, ... Conservation Biology 35 (1), 360-368, 2021 | 45 | 2021 |
| Orchid (Orchidaceae) decline in the Catoctin Mountains, Frederick County, Maryland as documented by a long-term dataset WM Knapp, R Wiegand Biodiversity and conservation 23 (8), 1965-1976, 2014 | 24 | 2014 |
| Improving species status assessments under the US Endangered Species Act and implications for multispecies conservation challenges worldwide RF Noss, JM Cartwright, D Estes, T Witsell, G Elliott, D Adams, M Albrecht, ... Conservation Biology 35 (6), 1715-1724, 2021 | 15 | 2021 |
| Taxonomy, morphology, and geographic distribution of Juncus longii (Juncaceae) WM Knapp, RFC Naczi Systematic botany 33 (4), 685-694, 2008 | 15 | 2008 |
| Regional records improve data quality in determining plant extinction rates WM Knapp, A Frances, R Noss, RFC Naczi, A Weakley, GD Gann, ... Nature Ecology & Evolution 4 (4), 512-514, 2020 | 11 | 2020 |
| Floristic discoveries in Delaware, Maryland, and Virginia WM Knapp, RFC Naczi, WD Longbottom, CA Davis, WA McAvoy, CT Frye, ... Phytoneuron 64, 1-26, 2011 | 11 | 2011 |
| Science needs of southeastern grassland species of conservation concern: A framework for species status assessments RF Noss, JM Cartwright, D Estes, T Witsell, KG Elliott, DS Adams, ... Open-File Report, 2021 | 10 | 2021 |
| Contributions to the lichen flora of Maryland: recent collections from the Delmarva Peninsula JC Lendemer, WM Knapp Opuscula Philolichenum 4, 23-40, 2007 | 10 | 2007 |
| The true identity of Marshallia grandiflora, an extinct species, and the description of Marshallia pulchra (Asteraceae, Helenieae, Marshalliinae) WM Knapp, DB Poindexter, AS Weakley Phytotaxa 447 (1), 1–15-1–15, 2020 | 8 | 2020 |
| Data sharing for conservation: A standardized checklist of US native tree species and threat assessments to prioritize and coordinate action C Carrero, E Beckman Bruns, A Frances, D Jerome, W Knapp, A Meyer, ... Plants, People, Planet 5 (4), 600-616, 2023 | 7 | 2023 |
| Vascular plants of Maryland, USA: A comprehensive account of the state's botanical diversity WM Knapp, RFC Naczi Smithsonian Scholarly Press, 2021 | 6 | 2021 |
| Gratiola brevifolia (Plantaginaceae) new to the flora of Delaware, the Delmarva Peninsula, and the mid-Atlantic WM Knapp, D Estes SIDA, Contributions to Botany, 825-829, 2006 | 4 | 2006 |
| Riverscour Ecosystems of Eastern Unglaciated North America: A Review D Estes, C Tracey, E Zimmerman, W Knapp, J Vanderhorst, J Singhurst, ... Natural Areas Journal 43 (3), 148-168, 2023 | 3 | 2023 |
| Juncaceae: The Rush Family WM Knapp, RFC Naczi New York Botanical Garden Press, 2016 | 3 | 2016 |
| Juncus fascinatus (Juncaceae), a new combination in Juncus sect. Ozophyllum and notes on morphologically similar species WM Knapp Phytotaxa 174 (5), 243–260-243–260, 2014 | 3 | 2014 |
| Rhynchospora marliniana (Cyperaceae), a new species of Rhynchospora sect. Plumosae from northern Central America and southeastern North America RFC Naczi, WM Knapp, WW Thomas Kew Bulletin 67, 771-778, 2012 | 3 | 2012 |
| A new Sisyrinchium (Iridaceae) from cedar glades in northern Alabama BA Sorrie, WM Knapp, LD Estes, DD Spaulding Journal of the Botanical Research Institute of Texas, 323-329, 2012 | 3 | 2012 |
| An annotated check list of the liverworts and hornworts of the Delmarva Peninsula WA McAvoy, WM Knapp, LT Biechele The Journal of the Torrey Botanical Society 138 (2), 239-251, 2011 | 3 | 2011 |
| Ecological Classification of Groundwater-Fed Seepage Wetlands of the Maryland Coastal Plain JW Harrison, WM Knapp Maryland Department of Natural Resources, Wildlife and Heritage Service …, 2010 | 3 | 2010 |
| New Records for the Leafy Liverwort Calypogeia peruviana Nees et Mont.(Calypogeiaceae) on the Delmarva Peninsula WA MCAVOY, LT BIECHELE, WM KNAPP Evansia 23, 19-20, 2006 | 2 | 2006 |
Robert NacziCurator of North American Botany, The New York Botanical GardenVerified email at nybg.org
