| Rumex conglomeratus x pulcher = R. x muretii | GB, VC17 Surrey, Littleworth Common, Esher | Charles Edward Britton | Botanical Society & Exchange Club of The British Isles Charles Edward Britton | 8/8/1926 | MANCH |
| Rumex hydrolapathum | GB, VC36 Herefordshire, Little Birch | Augustin Ley | Botanical Society & Exchange Club of The British Isles William Hadden Beeby | 6/9/1887 | SLBI |
| Rumex pulcher | GB, VC20 Hertfordshire, Hitchin | Joseph Edward Little | Botanical Society & Exchange Club of The British Isles Job Edward Lousley | 26/7/1923 to 17/9/1923 | SLBI |
| Rumex sanguineus x obtusifolius = R. x dufftii | GB, VC17 Surrey, Littleworth Common, Esher | Charles Edward Britton | Botanical Society & Exchange Club of The British Isles Charles Edward Britton | 27/7/1913 | MANCH |
| Salicornia europaea | GB, VC11 South Hampshire, Hayling Island | Edward Shearburn Marshall | Botanical Society & Exchange Club of The British Isles Frederick Townsend | 13/9/1900 | SLBI |
| Salicornia ramosissima | GB, VC11 South Hampshire, Hayling Island | Patrick Martin Hall | Botanical Society & Exchange Club of The British Isles Harold Stuart Thompson | 30/9/1933 | BIRM |
| Salicornia ramosissima | GB, VC19 North Essex, Alresford | George Charles Brown | Botanical Society & Exchange Club of The British Isles George Charles Brown Job Edward Lousley | 16/9/1934 | SLBI |
| Salicornia ramosissima | GB, VC19 North Essex, Alresford | George Charles Brown | Botanical Society & Exchange Club of The British Isles George Charles Brown | 10/9/1934 | SLBI |
| Salix alba subsp. vitellina | GB, VC55 Leicestershire, Scraptoft | Arthur Reginald Horwood | Botanical Society & Exchange Club of The British Isles National Museum of Wales | 8/1926 | SLBI |
| Salix aurita x repens = S. x ambigua | GB, VC33 East Gloucestershire, Todenham | Harry Joseph Riddelsdell | Botanical Society & Exchange Club of The British Isles | 5/8/1915 | CGE |
| Salix caprea x aurita = S. x capreola | GB, VC20 Hertfordshire, Hitchin | Joseph Edward Little | Botanical Society & Exchange Club of The British Isles Joseph Edward Little | 4/8/1922 16/3/1923 29/3/1924 28/6/1924 | MANCH |
| Salix caprea x cinerea = S. x reichardtii | GB, VC20 Hertfordshire, Ippolyts Common | Joseph Edward Little | Botanical Society & Exchange Club of The British Isles | 14/4/1924 to 18/7/1924 | MANCH |
| Salix caprea x cinerea = S. x reichardtii | GB, VC29 Cambridgeshire, Langley Wood | Edmund Frederic Warburg | Botanical Society & Exchange Club of The British Isles | 9/6/1932 | CGE |
| Salix caprea x cinerea = S. x reichardtii | GB, VC59 South Lancashire, Walton Cultivated | James Alfred Wheldon | Botanical Society & Exchange Club of The British Isles | 4/1916 8/1916 | CGE |
| Salix cinerea | GB, VC19 North Essex, East Donyland | George Charles Brown | George Charles Brown Botanical Society & Exchange Club of The British Isles | 14/3/1926 15/8/1926 | MANCH |
| Salix cinerea x aurita = S. x multinervis | GB, VC20 Hertfordshire, Oughton Head | Joseph Edward Little | Botanical Society & Exchange Club of The British Isles | 12/4/1924 27/6/1924 | MANCH |
| Salix cinerea x aurita = S. x multinervis | GB, VC20 Hertfordshire, Oughtonhead | Joseph Edward Little | Botanical Society & Exchange Club of The British Isles Joseph Edward Little | 12/4/1924 27/6/1924 | MANCH |
| Salix fragilis x alba = S. x rubens | GB, VC20 Hertfordshire, Little Wymondley | Joseph Edward Little | Botanical Society & Exchange Club of The British Isles Joseph Edward Little | 3/6/1924 | MANCH |
+ | Salix myrsinites | GB, VC111 Orkney, Hoy | Henry Halcro Johnston | Botanical Society & Exchange Club of The British Isles George Claridge Druce Mary Hayward | 13/5/1926 | MANCH |
| Salix pentandra x fragilis = S. x meyeriana | GB, VC20 Hertfordshire, Hitchin | Joseph Edward Little | Botanical Society & Exchange Club of The British Isles | 22/5/1924 14/8/1924 | MANCH |
| Salix pentandra x fragilis = S. x meyeriana | GB, VC47 Montgomeryshire, Glyn Cogan | Henry Haselfoot Haines | Botanical Society & Exchange Club of The British Isles | 4/1944 | CGE |
| Salix purpurea | GB, VC62 North-east Yorkshire, Catton | Catherine Muriel Rob | Botanical Society & Exchange Club of The British Isles Catherine Muriel Rob | 6/4/1946 30/6/1946 | SLBI |
| Salix triandra | GB, VC8 South Wiltshire, Boyton | | Botanical Society & Exchange Club of The British Isles Joseph Donald Grose | 24/8/1947 | SLBI |
| Salix viminalis x caprea = S. x smithiana | GB, VC6 North Somerset, Walton in Gordano | James Walter White | Botanical Society & Exchange Club of The British Isles | 4/1887 to 8/1887 | LIV |
| Salix viminalis x caprea = S. x smithiana | GB, VC19 North Essex, Berechurch | George Charles Brown | Botanical Society & Exchange Club of The British Isles Joseph Edward Little | 21/5/1923 to 14/8/1923 | CGE |
+ | Salix viminalis x caprea x cinerea = S. x calodendron | GB, VC20 Hertfordshire, Ickleford | Joseph Edward Little | Botanical Society & Exchange Club of The British Isles Willis Openshaw Howarth | 2/11/1923 to 16/5/1924 | MANCH |
| Salix viminalis x cinerea = S. x holosericea | GB, VC17 Surrey, Tilburstow Hill | | Botanical Society & Exchange Club of The British Isles J Fraser | 14/4/1929 to 7/7/1929 | MANCH |
| Salix viminalis x cinerea = S. x holosericea | GB, VC38 Warwickshire, Kenilworth | Henry Bromwich | Botanical Society & Exchange Club of The British Isles Charles Bailey | | MANCH |
| Salix x viridis | GB, VC7 North Wiltshire, Wroughton | Joseph Donald Grose | Botanical Society & Exchange Club of The British Isles Joseph Donald Grose | 8/5/1945 10/6/1945 | SLBI |
+ | Saxifraga hypnoides | IE, VCH9 Co. Clare, Black Head | Edward Shearburn Marshall | Botanical Society & Exchange Club of The British Isles Charles Bailey | 16/5/1918 | MANCH |
| Saxifraga umbrosa | IE, VCH3 West Cork, Ballyrisode House | Patrick Martin Hall | Botanical Society & Exchange Club of The British Isles Patrick Martin Hall | 17/5/1936 | SLBI |
| Schoenoplectus tabernaemontani | GB, VC7 North Wiltshire, Christian Malford | Joseph Donald Grose | Botanical Society & Exchange Club of The British Isles Joseph Donald Grose | 17/6/1945 | SLBI |
| Schoenoplectus tabernaemontani | GB, VC7 North Wiltshire, Christian Malford | | Botanical Society & Exchange Club of The British Isles Joseph Donald Grose | 22/8/1945 | SLBI |
| Schoenoplectus tabernaemontani | GB, VC7 North Wiltshire, Christian Malford | Joseph Donald Grose | Botanical Society & Exchange Club of The British Isles Joseph Donald Grose | 17/6/1945 22/8/1945 | SLBI |
| Scrophularia umbrosa | GB, VC8 South Wiltshire, Shalbourne | | Botanical Society & Exchange Club of The British Isles Joseph Donald Grose | 7/8/1935 | SLBI |
| Scrophularia umbrosa | GB, VC8 South Wiltshire, Shalbourne | | Botanical Society & Exchange Club of The British Isles Joseph Donald Grose | 7/8/1935 | K |
| Scrophularia umbrosa | GB, VC28 West Norfolk, Scoulton | Job Edward Lousley | Botanical Society & Exchange Club of The British Isles | 11/10/1934 | K |
| Scrophularia umbrosa | GB, VC28 West Norfolk, Scoulton | Job Edward Lousley | Botanical Society & Exchange Club of The British Isles Job Edward Lousley | 11/10/1934 | K |
| Scrophularia vernalis | GB, VC49 Caernarvonshire, Gloddaeth | Job Edward Lousley | Botanical Society & Exchange Club of The British Isles Job Edward Lousley | 8/6/1931 | K |
| Senecio squalidus | GB, VC21 Middlesex, City of London | Noel Yvri Sandwith | Botanical Society & Exchange Club of The British Isles | 14/9/1943 | SLBI |