| 
                                    Castilleja latebracteata Pennell
                                 | 
                                C. S. Williamson s.n. | 
                                27 Apr 1903 | 
                                United States of America | 
                                — | 
                                High bridge of Pecos [?]. | 
                                isotype | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Lythrum salicaria L.
                                 | 
                                C. S. Williamson 1272 | 
                                06 Aug 1910 | 
                                Canada | 
                                Quebec | 
                                Montmorency Falls | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Pinus banksiana Lamb.
                                 | 
                                C. S. Williamson 1015 | 
                                24 Jul 1911 | 
                                Canada | 
                                Quebec | 
                                L'Islet du Massacre, Bic | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Penstemon smallii A.Heller
                                 | 
                                C. S. Williamson s.n. | 
                                August | 
                                United States of America | 
                                North Carolina | 
                                Balsam | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Amaranthus pumilus Raf.
                                 | 
                                C. S. Williamson s.n. | 
                                — | 
                                United States of America | 
                                North Carolina | 
                                Seacoast near Wilmington. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Amaranthus pumilus Raf.
                                 | 
                                C. S. Williamson s.n. | 
                                01 Sep | 
                                United States of America | 
                                North Carolina | 
                                Sea Beach near Wrightsville | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Sphagnum teres (Schimp.) Ångstr.
                                 | 
                                C. S. Williamson  | 
                                07 Aug 1911 | 
                                Canada | 
                                Newfoundland and Labrador | 
                                Caribou Island, Battle Harbour, Labrador | 
                                — | 
                                 | 
                                 | 
                                
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Cytisus scoparius (L.) Link
                                 | 
                                C. S. Williamson s.n. | 
                                15 May 1910 | 
                                United States of America | 
                                Pennsylvania | 
                                Crum Lynn Station | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Juniperus horizontalis Moench
                                 | 
                                C. S. Williamson 2287 | 
                                — | 
                                United States of America | 
                                Michigan | 
                                Keweenaw Co. Rock Harbor, Isle… | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Picea glauca (Moench) Voss var. glauca
                                 | 
                                C. S. Williamson 1019 | 
                                15 Jul 1911 | 
                                Canada | 
                                Quebec | 
                                Bic | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Eriocaulon parkeri B.L.Rob.
                                 | 
                                C. S. Williamson s.n. | 
                                28 Jul 1906 | 
                                United States of America | 
                                New Jersey | 
                                Camden Co. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Eriocaulon parkeri B.L.Rob.
                                 | 
                                C. S. Williamson s.n. | 
                                02 Oct 1905 | 
                                United States of America | 
                                New Jersey | 
                                Camden Co. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Selaginella acanthonota Underw.
                                 | 
                                C. S. Williamson s.n. | 
                                Jul 1892 | 
                                United States of America | 
                                North Carolina | 
                                Wilmington | 
                                holotype | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Marshallia williamsonii Small
                                 | 
                                C. S. Williamson s.n. | 
                                02 Sep 1900 | 
                                United States of America | 
                                North Carolina | 
                                Wilmington | 
                                holotype | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Thuja occidentalis L.
                                 | 
                                C. S. Williamson 1020 | 
                                13 Jul 1911 | 
                                Canada | 
                                Quebec | 
                                Bic | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Zygophyllum fabago L.
                                 | 
                                C. S. Williamson s.n. | 
                                — | 
                                United States of America | 
                                Pennsylvania | 
                                Karghn [?Karghn's] | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Echinochloa crus-galli (L.) P.Beauv.
                                 | 
                                C. S. Williamson s.n. | 
                                s.d. | 
                                United States of America | 
                                Pennsylvania | 
                                Philadelphia Co. Philadelphia | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Eragrostis pectinacea (Michx.) Nees
                                 | 
                                C. S. Williamson s.n. | 
                                s.d. | 
                                United States of America | 
                                Pennsylvania | 
                                Philadelphia Co. Philadelphia | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Eragrostis refracta (Muhl.) Scribn.
                                 | 
                                C. S. Williamson s.n. | 
                                30 Aug 1900 | 
                                United States of America | 
                                North Carolina | 
                                Weldon | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Arabidopsis thaliana (L.) Heynh.
                                 | 
                                C. S. Williamson s.n. | 
                                [collector lived 1857-1914] | 
                                United States of America | 
                                Pennsylvania | 
                                Philadelphia Co. | 
                                — | 
                                 | 
                                 | 
                                
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Carya illinoinensis (Wangenh.) K.Koch
                                 | 
                                C. S. Williamson s.n. | 
                                12 Jul 1908 | 
                                United States of America | 
                                New York | 
                                Cape May | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Carya ovata (Mill.) K.Koch
                                 | 
                                C. S. Williamson s.n. | 
                                May | 
                                — | 
                                — | 
                                Phil a | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Juglans cinerea L.
                                 | 
                                C. S. Williamson s.n. | 
                                17 May 1908 | 
                                United States of America | 
                                Pennsylvania | 
                                Montgomery Co. Sumneytown | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Agropyron Gaertn.
                                 | 
                                C. S. Williamson s.n. | 
                                Aug | 
                                — | 
                                — | 
                                Phil [Note: no country, state]. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Agrostis perennans (Walter) Tuck.
                                 | 
                                C. S. Williamson 771 | 
                                18 Aug 1911 | 
                                United States of America | 
                                New York | 
                                St. John's. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Agrostis stolonifera L.
                                 | 
                                C. S. Williamson 770 | 
                                18 Aug 1911 | 
                                — | 
                                — | 
                                St. John's. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Aira praecox L.
                                 | 
                                C. S. Williamson s.n. | 
                                May 30th-June 7th 1908 | 
                                United States of America | 
                                New York | 
                                Cold Spring, 2 Point Pleasant. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Alopecurus geniculatus L.
                                 | 
                                C. S. Williamson 292 | 
                                16 Jul 1911 | 
                                — | 
                                — | 
                                Whitbourne. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Alopecurus pratensis L.
                                 | 
                                C. S. Williamson 704 | 
                                11 Aug 1911 | 
                                — | 
                                — | 
                                Battle Harbor [Lake]. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Andropogon glomeratus var. glomeratus
                                 | 
                                C. S. Williamson s.n. | 
                                Sep 1906 | 
                                United States of America | 
                                Pennsylvania | 
                                Lester, PA | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Andropogon gyrans Ashe var. gyrans
                                 | 
                                C. S. Williamson s.n. | 
                                06 Nov 1910 | 
                                United States of America | 
                                Pennsylvania | 
                                Radnor | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Bromus ciliatus L.
                                 | 
                                C. S. Williamson 1442 | 
                                21 Jul 1910 | 
                                Canada | 
                                Quebec | 
                                Bic | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Arundinaria
                                 | 
                                C. S. Williamson s.n. | 
                                s.d. | 
                                United States of America | 
                                North Carolina | 
                                Weldon | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Calamagrostis canadensis (Michx.) P.Beauv.
                                 | 
                                C. S. Williamson 703 | 
                                10 Aug 1911 | 
                                — | 
                                — | 
                                Battle Harbor Lat. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Calamagrostis canadensis (Michx.) P.Beauv.
                                 | 
                                C. S. Williamson 536 | 
                                02 Aug 1911 | 
                                — | 
                                — | 
                                Harbor Grace. [Njer?]. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Calamagrostis canadensis (Michx.) P.Beauv.
                                 | 
                                C. S. Williamson 1034 | 
                                Aug 1912 | 
                                — | 
                                — | 
                                Mont[mvrency Falls]. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Calamagrostis canadensis (Michx.) P.Beauv.
                                 | 
                                C. S. Williamson 2303 | 
                                August 15-16, 1912 | 
                                United States of America | 
                                Michigan | 
                                Isle Royale. Johnson's Island. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Calamagrostis canadensis (Michx.) P.Beauv.
                                 | 
                                C. S. Williamson 822 | 
                                04 Sep 1911 | 
                                United States of America | 
                                New Jersey | 
                                Atsion. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Calamagrostis neglecta subsp. inexpansa (A.Gray) Tzvelev
                                 | 
                                C. S. Williamson 2289 | 
                                August 15-16, 1912 | 
                                United States of America | 
                                Michigan | 
                                Isle Royale. Johnson's Island. Rock… | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Calamagrostis pickeringii A.Gray
                                 | 
                                C. S. Williamson 791 | 
                                18 Aug 1911 | 
                                Canada | 
                                Newfoundland and Labrador | 
                                St. John's | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Coleataenia anceps (Michx.) Soreng
                                 | 
                                C. S. Williamson s.n. | 
                                29 Aug 1800 | 
                                United States of America | 
                                Virginia | 
                                Virginia Beach | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Glyceria canadensis (Michx.) Trin.
                                 | 
                                C. S. Williamson 734 | 
                                16 Aug 1911 | 
                                — | 
                                — | 
                                St. John's. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Glyceria canadensis (Michx.) Trin.
                                 | 
                                C. S. Williamson 1443 | 
                                23 Jul 1910 | 
                                Canada | 
                                Quebec | 
                                St. Fabien. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Glyceria obtusa (Muhl.) Trin.
                                 | 
                                C. S. Williamson 368 | 
                                21 Jul 1911 | 
                                — | 
                                — | 
                                Placenha [Nfed]. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Glyceria septentrionalis Hitchc.
                                 | 
                                C. S. Williamson 733 | 
                                18 Aug 1911 | 
                                United States of America | 
                                New Jersey | 
                                St. John's. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Glyceria striata (Lam.) Hitchc.
                                 | 
                                C. S. Williamson 245 | 
                                16 Jul 1911 | 
                                — | 
                                — | 
                                Whitbourne [Mld] | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Panicum amarum var. amarum
                                 | 
                                C. S. Williamson s.n. | 
                                29 Aug 1900 | 
                                United States of America | 
                                Virginia | 
                                Virginia Beach | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Panicum capillare L.
                                 | 
                                C. S. Williamson s.n. | 
                                19 Sep 1908 | 
                                United States of America | 
                                New Jersey | 
                                Riddleton. | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Panicum L.
                                 | 
                                C. S. Williamson s.n. | 
                                02 Sep 1906 | 
                                United States of America | 
                                North Carolina | 
                                Welmington | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 | 
                            
                       
                        
                            
                            
                                | 
                                    Panicum L.
                                 | 
                                C. S. Williamson s.n. | 
                                02 Sep 1900 | 
                                United States of America | 
                                North Carolina | 
                                Welmington | 
                                — | 
                                 | 
                                 | 
                                
                                                                      
                                                                  | 
                                
                                    
                                 |