| Lathyrus tuberosus | GB, VC18 South Essex, Canvey Island | Frederick Arnold Lees William Williamson Newbould | Frederick Arnold Lees William Hadden Beeby | 21/6/1872 | SLBI |
| Lepidium draba | GB, VC15 East Kent, Ramsgate | William Williamson Newbould | | 7/1843 | SLBI |
| Limonium humile | GB, VC13 West Sussex, Chichester | | Frederick Townsend William Williamson Newbould | 7/1843 | SLBI |
| Limonium vulgare | GB, VC113 Channel Islands, Saint Sampson's, Guernsey | William Williamson Newbould | | 1/9/1835 | SLBI |
| Lotus subbiflorus | GB, VC113 Channel Islands, Guernsey, Saint Martin's | William Williamson Newbould | Frederick Townsend | 8/1841 | SLBI |
| Ludwigia palustris | GB, VC113 Channel Islands, Jersey, Saint Peters | William Williamson Newbould | Allan Octavian Hume Frederick Townsend | 1846 | SLBI |
| Lythrum hyssopifolia | GB, VC113 Channel Islands, Jersey, Saint Catherine's Bay | William Williamson Newbould | Allan Octavian Hume Frederick Townsend | 8/7/1842 | SLBI |
| Matricaria recutita | GB | William Williamson Newbould | Frederick Townsend | 10/8/1852 | SLBI |
| Medicago sativa subsp. falcata | GB, VC26 West Suffolk, Thetford | William Williamson Newbould | Frederick Townsend | 15/8/1851 | SLBI |
| Mentha pulegium | GB, VC31 Huntingdonshire, Earith | William Williamson Newbould | Frederick Townsend | 9/1884 | SLBI |
| Myrrhis odorata | GB, VC57 Derbyshire, Hathersage | William Williamson Newbould | Allan Octavian Hume Frederick Townsend | 7/11/1846 | SLBI |
| Oxalis corniculata | GB, VC113 Channel Islands, Jersey, Saint Peters | William Williamson Newbould | Allan Octavian Hume Frederick Townsend | 18/8/1842 | SLBI |
| Persicaria mitis | GB, VC31 Huntingdonshire, Bluntisham | William Williamson Newbould | Frederick Townsend | 1845 | SLBI |
| Petroselinum segetum | GB, VC31 Huntingdonshire, Bluntisham | William Williamson Newbould | Allan Octavian Hume Frederick Townsend | 9/1845 | SLBI |
| Petroselinum segetum | GB, VC31 Huntingdonshire, Bluntisham | William Williamson Newbould | Frederick Townsend | 9/1845 | SLBI |
| Peucedanum palustre | GB, VC31 Huntingdonshire, Holme | William Williamson Newbould | Allan Octavian Hume | 16/9/1845 | SLBI |
| Polygonum aviculare | GB, VC17 Surrey, Norwood | Frederick Townsend William Williamson Newbould | Allan Octavian Hume | 27/8/1864 | SLBI |
| Polygonum oxyspermum | GB, VC113 Channel Islands, Guernsey | William Williamson Newbould | Frederick Townsend | 1841 | SLBI |
| Potamogeton coloratus | GB, VC29 Cambridgeshire, Bottisham Fen | William Williamson Newbould | Allan Octavian Hume Frederick Townsend | 23/7/1847 | SLBI |
| Potamogeton gramineus | GB, VC29 Cambridgeshire, Wicken Fen | William Williamson Newbould | Allan Octavian Hume Frederick Townsend | 8/5/1851 | SLBI |
| Potamogeton natans | GB, VC49 Caernarvonshire, Cwmffynnon | William Williamson Newbould | Frederick Townsend | 19/8/1847 | SLBI |
| Potamogeton pectinatus | GB, VC31 Huntingdonshire, Bluntisham | William Williamson Newbould | Frederick Townsend | 23/6/1846 | SLBI |
| Potamogeton polygonifolius | GB, VC29 Cambridgeshire, Bottisham Fen | William Williamson Newbould | William Williamson Newbould | 23/7/1847 | SLBI |
| Potamogeton polygonifolius | GB, VC63 South-west Yorkshire, Loxley | William Williamson Newbould | William Hadden Beeby | 7/6/1846 | SLBI |
| Ranunculus baudotii | GB, VC28 West Norfolk, Burnham Norton | William Williamson Newbould | Allan Octavian Hume Charles Cardale Babington Frederick Townsend | 24/5/1852 | SLBI |
| Ranunculus parviflorus | GB, VC29 Cambridgeshire, Comberton | William Williamson Newbould | Allan Octavian Hume Frederick Townsend | | SLBI |
| Rubus latifolius | GB, VC83 Midlothian, Cramond Bridge | William Williamson Newbould | | 8/11/1846 | SLBI |
| Rubus latifolius | GB, VC83 Midlothian, Edinburgh | William Williamson Newbould | | 1846 | SLBI |
| Rumex crispus subsp. elongatus | | | Frederick Townsend William Williamson Newbould | 5/7/1873 | SLBI |
| Rumex crispus x obtusifolius = R. x pratensis | GB, VC19 North Essex, Broxbourne | William Williamson Newbould | Allan Octavian Hume Frederick Townsend | 19/7/1848 | SLBI |
| Rumex maritimus | GB, VC31 Huntingdonshire, Bluntisham | William Williamson Newbould | Frederick Townsend | 13/9/1845 | SLBI |
| Rumex maritimus | GB, VC31 Huntingdonshire, Holme Fen | William Williamson Newbould | Frederick Townsend | 16/9/1845 | SLBI |
| Rumex obtusifolius var. sylvestris | GB, VC17,VC21, Putney | William Williamson Newbould | Frederick Townsend | | SLBI |
| Ruppia rostellata | GB, VC13 West Sussex, Chichester | William Williamson Newbould | Frederick Townsend | 9/1844 | SLBI |
| Sagittaria sagittifolia | GB, VC13 West Sussex, Chichester | William Williamson Newbould | Frederick Townsend | 10/1846 | SLBI |
| Sagittaria sagittifolia | GB, VC31 Huntingdonshire, Bluntisham | William Williamson Newbould | Frederick Townsend | 5/1845 | SLBI |
| Schoenoplectus lacustris | GB, VC31 Huntingdonshire, Bluntisham | William Williamson Newbould | Frederick Townsend | 6/1846 | SLBI |
| Schoenoplectus pungens | GB, VC113 Channel Islands, Saint Ouen's Pond | William Williamson Newbould | Frederick Townsend | 8/1842 | SLBI |
| Scleranthus annuus | GB, VC28 West Norfolk, Thetford | William Williamson Newbould | Allan Octavian Hume Frederick Townsend | 4/7/1848 | SLBI |
| Scrophularia scorodonia | GB, VC113 Channel Islands, Jersey, Saint Peters | William Williamson Newbould | Allan Octavian Hume Frederick Townsend | 8/5/1842 | SLBI |