Construction of the first edition of this tool was made possible by the consistent and solid support in terms of the facility, equipment, seed collection, and expertise provided to Julia Scher at the Seed Lab in CDFA's Plant Pest Diagnostis Center (PPDC), under the direction of Dennis Mayhew and subsequently Umesh Kodira of CDFA. Offering help at various times throughout development were: Marc Epstein, Ray Gill, Fred Hrusa, Scott Kinnee, Tim Tyler, and Shaun Winterton. In particular, this tool could not have been developed without the help of the PPDC Seed Lab botanists, which was essential for its successful completion; many thanks go to Jim Effenberger, Deborah Meyer, Paul Peterson, and Marian Stephenson for numerous helpful discussions, expert advice and opinions, and consistent, all-around assistance during development of all aspects of the key. Julia also wishes to thank: Rodney Young (PPQ) and Mark Thurmond (PPQ) for their gracious help during the author’s visit to examine and photograph specimens in the collections at the Seed Examination Facility, Beltsville; Jack Kelly Clark (UC Davis) for his invaluable advice on photographic techniques; Lawrence Alice (Western Kentucky University) for essential information regarding the Rubus fruticosus complex for treatment of that group in the key; Robert Gibbons (PPQ) for scanning original drawings by Lynda E. Chandler; Matthew Johnson (Desert Legume Program) for his kind donation of Prosopis seeds and pods; and Ing. Ramon Palacios of the Universidad de Buenos Aires for the very generous gift of rare Prosopis pods. Julia sends a special thank you to Matthew Taylor and the CBIT staff, for advice and guidance in the development of this key, and especially for always being courteous and helpful in the face of numerous and often last-minute technical questions and requests.
For Edition 2.0 of the tool, Deena Walters wishes to thank Deborah Meyer and Jim Effenberger of CDFA for the loan of various disseminules for photography and observation. Rodney Young provided Deena with specimens of Senecio inaequidens, S. madagascariensis, and Inula britannica. Matthew Johnson, of the Desert Legume Program, University of Arizona, kindly donated seeds of Acacia nilotica. For technical and moral support, Deena thanks Julia Scher and Todd Gilligan. Conversations with Alan Tasker, who is the National Noxious Weed Program Manager at APHIS, were invaluable for clarifying the process of listing federal noxious weeds.
In August 2010, Edition 2.1 of the tool was designed and programmed by Matthew Trice.
Amanda Redford coordinated the redesign for Edition 2.2 in February 2015, with programming assistance from Brandon Dewey.
All photographic images were produced by the authors except where acknowledged in image captions. See Copyright, citation and disclaimers for proper citation of images.
The majority of original illustrations were drawn by Lesley Randall. The remainder were drawn by Ingrid Hogle and Julia Scher.
Drawings by Lynda E. Chandler are from Gunn and Ritchie (1988).
The authors thank those who allowed use of their original photographic images: Donovan Bailey (New Mexico State University), Board of Trustees of the Royal Botanic Gardens — Kew, Christo Botha (University of Pretoria, South Africa), Bugwood (University of Georgia), P. Busselen (Katholiekd Universiteit Leuven), John Clayton (NIWA - National Institute of Water & Atmospheric Research, New Zealand), David Du Puy (Scottish Gardens), EcoPort, Chris Evans (River to River CWMA), C.W. Fagg, Amy Ferriter (State of Idaho), J.M. Garg, Peggy Greb (USDA/ARS), R.J. Helton (CDFA, Integrated Pest Control), Fred Hrusa (CDFA), Mariana Jooste, Neal Kramer, James R. Manhart (Texas A&M University), Sheldon Navie, Richard Old (XID Services, Inc.), nipplerings72 (flickr), Victor Ramey (University of Florida), Barry A. Rice (The Nature Conservancy), Tony Rodd, Forest and Kim Starr (United States Geological Survey), Philip A. Thomas, Mark Thurmond (PPQ), Laurent Toussaint, University of Florida/IFAS Center for Aquatic and Invasive Plants, Shaun L. Winterton, Rachel Woodfield (Merkel & Associates), Rodney Young (PPQ), H.G. Zimmermann (ARC-PPRI - Plant Protection Research Institute, South Africa). Permission must be sought from the credit holders to reproduce any images in this tool.
Character matrix data and original disseminule descriptions (excluding internal structure) are based on personal observation and descriptions from various references, while data and descriptions for internal seed morphology are based primarily on Martin (1946) and Gunn and Ritchie (1988), employing Martin’s classification system, with modifications. Other content in the tool is derived from numerous works (listed in References).
The authors thank the following beta testers of Edition 1.0 for their helpful comments and suggestions: Lawrence Alice (Western Kentucky University); Ken Allison (Canadian Food Inspection Agency, Ontario); Jim Bruce (USDA, ARS, National Center for Genetic Resources Preservation); Larry Fowler (CPHST); Michael Gerdes (Syngenta Seeds); Robert Karrfalt (USDA Forest Service); Polly Lehtonen (PPQ, NIS); Deborah Meyer (Seed lab, CDFA); Wolfgang Stuppy (Royal Botanic Gardens, Kew); Kevin Thiele (CBIT); and Shaun Winterton (CDFA). The following individuals at CDFA provided valuable feedback by testing the keys with supplied unknowns: Jim Effenberger; Fred Hrusa, Don Joley, Marian Stephenson, Connie Weiner, and Irene Wibawa.
For beta testing Edition 2.0, the authors thank David F. Bitzel (USDA), Jim Effenberger (CDFA), Christopher W. Fagg (Universidade de Brasília), Ana Margina (PPQ, NIS), Deborah Meyer (CDFA), Sharon Talley (CPHST), Mark Towata (PPQ), and Ricardo Valdez (USDA). Also, Alan Tasker (APHIS) provided valuable suggestions after reviewing the fact sheets for the 11 taxa new to Edition 2.0.