| Zostera noltei | GB, VC85 Fifeshire, Burntisland | John Thomas Irvine Boswell-Syme | | 3/1874 | SLBI |
| Zostera angustifolia | GB, VC85 Fifeshire, Burntisland | John Thomas Irvine Boswell-Syme | | 3/1874 | BON |
| Zostera angustifolia | GB, VC85 Fifeshire, Burntisland | John Thomas Irvine Boswell-Syme | Augustin Ley | 3/1874 | BIRM |
| Zannichellia polycarpa | GB, VC111 Orkney, Loch of Kirbister | John Thomas Irvine Boswell-Syme | Botanical Exchange Club of The British Isles Allan Octavian Hume Frederick Townsend | 8/1880 | SLBI |
| Zannichellia palustris | GB, VC16 West Kent, Gravesend | John Thomas Irvine Boswell-Syme | Botanical Society of London John Thomas Irvine Boswell-Syme | 1855 | BON |
| Zannichellia palustris | GB, VC111 Orkney, Loch of Kirbister | John Thomas Irvine Boswell-Syme | Botanical Exchange Club of The British Isles Augustin Ley | 1880 | BIRM |
+ | Wolffia arrhiza | GB, VC21 Middlesex, Staines | John Thomas Irvine Boswell-Syme | Charles Bailey | 26/6/1866 | MANCH |
+ | Wolffia arrhiza | GB, VC21 Middlesex, Staines | John Thomas Irvine Boswell-Syme | Charles Bailey | 7/1866 | MANCH |
+ | Viola tricolor | GB, VC111 Orkney, Smoogro | John Thomas Irvine Boswell-Syme | Charles Bailey | 8/1880 | MANCH |
+ | Viola tricolor | GB, VC111 Orkney, Smoogro | John Thomas Irvine Boswell-Syme | Botanical Exchange Club of The British Isles Charles Bailey | 8/1880 | MANCH |
| Viola lutea | GB, VC85 Fifeshire, Auchtertool | J M Gray John Thomas Irvine Boswell-Syme | William Hillhouse | | BIRM |
| Viola hirta subsp. calcarea | GB, VC29 Cambridgeshire, Gog Magog Hills | Frederick Townsend | John Thomas Irvine Boswell-Syme William Hadden Beeby | 4/1847 | SLBI |
| Viola canina | GB, VC91 Kincardineshire, Kingcausie | John Thomas Irvine Boswell-Syme | Augustin Ley | 1881 | BIRM |
| Veronica fruticans | GB, VC88 Mid Perthshire, Breadalbane | John Thomas Irvine Boswell-Syme | Harold Stuart Thompson | 7/1851 | BIRM |
| Veronica alpina | GB, VC92 South Aberdeenshire, Lochnagar | John Thomas Irvine Boswell-Syme | Harold Stuart Thompson Thomas Clark John Thomas Irvine Boswell-Syme | 9/1851 | BIRM |
| Valeriana pyrenaica | GB, VC83 Midlothian, Edinburgh, Colinton Dell | John Thomas Irvine Boswell-Syme | Robert John Harvey-Gibson John Thomas Irvine Boswell-Syme | 1851 | ABS |
| Valeriana pyrenaica | GB, VC85 Fifeshire, Kinross | John Thomas Irvine Boswell-Syme | Augustin Ley | 7/1873 | BIRM |
| Valeriana pyrenaica | GB, VC85 Fifeshire, Kinross,Blair Adam | John Thomas Irvine Boswell-Syme | George Stephen West | 7/1873 | BIRM |
| Valeriana pyrenaica | GB, VC88 Mid Perthshire, Blair Atholl | John Thomas Irvine Boswell-Syme | William Hadden Beeby | 7/1873 | SLBI |
| Vaccinium oxycoccos | GB, VC85 Fifeshire, Cowdenbeath, Moss Morran | John Thomas Irvine Boswell-Syme | William Hadden Beeby | 6/1869 | SLBI |
| Urtica pilulifera | GB, VC25 East Suffolk, Lowestoft | John Thomas Irvine Boswell-Syme | Botanical Society of London George Stephen West John Thomas Irvine Boswell-Syme | 9/1850 | BIRM |
| Typha angustifolia | GB, VC17 Surrey, Wimbledon Common | John Thomas Irvine Boswell-Syme | Charles Ottley Groom | 1853 | BON |
| Tuberaria guttata | GB, VC113 Channel Islands, Jersey, Petit Port | John Thomas Irvine Boswell-Syme | Botanical Society of London Harold Stuart Thompson Thomas Clark John Thomas Irvine Boswell-Syme | 6/1853 | BIRM |
| Trifolium repens | GB, VC21 Middlesex, Hampstead Heath | John Thomas Irvine Boswell-Syme | | 9/1863 | BON |
| Trifolium ornithopodioides | GB, VC83 Midlothian, Musselburgh Links | John Thomas Irvine Boswell-Syme | John Thomas Irvine Boswell-Syme | 21/8/1847 | BON |
| Trifolium glomeratum | GB, VC16 West Kent, Green Street Green | John Thomas Irvine Boswell-Syme | | 6/1866 | BON |
| Trifolium agrarium | GB, VC85 Fifeshire, Balmuto | John Thomas Irvine Boswell-Syme | William Hadden Beeby | 8/1883 | SLBI |
| Tofieldia pusilla | GB, VC15 East Kent, Rochester | John Thomas Irvine Boswell-Syme | Mantua And Montferrat | 5/1853 | BON |
| Thalictrum minus subsp. majus | GB, VC85 Fifeshire, Balmuto Cultivated | John Thomas Irvine Boswell-Syme | Charles Bailey | 1874 | BIRM |
| Thalictrum minus subsp. majus | GB, VC85 Fifeshire, Balmuto Cultivated SE | John Thomas Irvine Boswell-Syme | Botanical Exchange Club of The British Isles Augustin Ley | 9/1880 | BIRM |
| Thalictrum minus subsp. majus | SE, Uppsala l, Uppsala Cultivated | John Thomas Irvine Boswell-Syme | Botanical Exchange Club of The British Isles Augustin Ley | 9/1879 | BIRM |
| Thalictrum minus subsp. arenarium | GB, VC85 Fifeshire, Kirkcaldy | John Thomas Irvine Boswell-Syme | Augustin Ley | 7/1871 | BIRM |
| Thalictrum minus | GB, VC29 Cambridgeshire, Gog Magog GB, VC85 Fifeshire, Balmuto Cultivated | John Thomas Irvine Boswell-Syme | Augustin Ley | 10/1877 | BIRM |
| Thalictrum minus | GB, VC29 Cambridgeshire, Gog Magog Hills | John Thomas Irvine Boswell-Syme | Augustin Ley | 10/1877 | BIRM |
| Thalictrum minus | GB, VC85 Fifeshire, Balmuto Cultivated | John Thomas Irvine Boswell-Syme | Charles Bailey | 7/1881 | BIRM |
| Thalictrum minus | GB, Lake District GB, VC85 Fifeshire, Balmuto Cultivated | John Thomas Irvine Boswell-Syme | Augustin Ley | 10/1877 | BIRM |
| Thalictrum minus | GB, VC85 Fifeshire, Balmuto Cultivated | John Thomas Irvine Boswell-Syme | Augustin Ley | 10/1877 | BIRM |
| Thalictrum minus var. oderatum | GB, VC85 Fifeshire, Balmuto Cultivated | John Thomas Irvine Boswell-Syme | Augustin Ley Edward Francis Linton | 8/1870 | BIRM |
| Thalictrum minus | GB, VC85 Fifeshire, North Queensferry | John Thomas Irvine Boswell-Syme | Harold Stuart Thompson Thomas Clark | 6/1851 | BIRM |
| Thalictrum minus | GB, VC85 Fifeshire, North Queensferry | John Thomas Irvine Boswell-Syme | George Stephen West John Gilbert Baker | 6/1857 | BIRM |