| Rubus adamsii | GB, VC24 Buckinghamshire, Beamond End | William Charles Richard Watson | | 31/7/1950 | SLBI |
| Rubus adenanthoides | GB, VC39 Staffordshire, Kinver | Eric Smoothy Edees | William Charles Richard Watson | 19/7/1952 | SLBI |
| Rubus adenanthoides | GB, VC39 Staffordshire, Kinvere | William Charles Richard Watson | | 19/7/1952 | SLBI |
| Rubus adenoleucus | GB, VC21 Middlesex, Scratchwood | William Charles Richard Watson | William Charles Richard Watson | 19/6/1950 | SLBI |
| Rubus affinis | GB, VC16 West Kent, Bickley Cultivated | | William Charles Richard Watson | 3/8/1950 | SLBI |
| Rubus ahenifolius | GB, VC17 Surrey, Woking | William Charles Richard Watson | | 6/8/1938 | SLBI |
| Rubus ahenifolius | GB, VC17 Surrey, Woking | William Charles Richard Watson | William Charles Richard Watson | 6/8/1938 | SLBI |
| Rubus albionis | GB, VC13 West Sussex, Petworth, Bognor Common | William Charles Richard Watson | William Charles Richard Watson | 19/7/1936 | SLBI |
| Rubus altiarcuatus | GB, VC4 North Devon, Lynton,Watersmeet | William Charles Richard Watson | William Charles Richard Watson | 2/7/1951 | SLBI |
| Rubus altiarcuatus | GB, VC4 North Devon, Watersmeet | William Charles Richard Watson | William Charles Richard Watson | 2/7/1951 | SLBI |
| Rubus amplificatus | GB, VC30 Bedfordshire, Dagnall | William Charles Richard Watson | William Charles Richard Watson | 29/7/1946 | SLBI |
| Rubus amplificatus | GB, VC30 Bedfordshire, Dagnall | William Charles Richard Watson | William Charles Richard Watson | 29/7/1946 | SLBI |
| Rubus amplificatus | GB, VC30 Bedfordshire, Dagnall | William Charles Richard Watson | | 29/7/1946 | SLBI |
| Rubus amplificatus | GB, VC36 Herefordshire, Aconbury | John Ezra Woodhead | William Charles Richard Watson | 11/7/1954 | SLBI |
| Rubus amplificatus | GB, VC39 Staffordshire, Swindon | Eric Smoothy Edees | William Charles Richard Watson | 19/7/1952 | SLBI |
| Rubus andegavensis | GB, VC16 West Kent, Westerham | William Charles Richard Watson | William Charles Richard Watson | 22/7/1938 | SLBI |
| Rubus anglocandicans | GB, VC30 Bedfordshire, Sandy Heath | William Charles Richard Watson | William Charles Richard Watson | 31/7/1946 | SLBI |
| Rubus anglocandicans | GB, VC39 Staffordshire, Clifton Campville | Eric Smoothy Edees | William Charles Richard Watson | 27/8/1946 | SLBI |
| Rubus anglocandicans | GB, VC39 Staffordshire, Haunton | Eric Smoothy Edees | William Charles Richard Watson | 27/8/1946 | SLBI |
| Rubus anglofuscus | GB, VC16 West Kent, Rusthall Common | William Charles Richard Watson | | | SLBI |
| Rubus anglofuscus | GB, VC17 Surrey, Limpsfield Cultivated | William Charles Richard Watson | William Charles Richard Watson | 21/7/1944 | SLBI |
| Rubus angloserpens | GB, VC36 Herefordshire, Upper Sapey | William Charles Richard Watson | | 23/8/1928 | SLBI |
| Rubus angloserpens | GB, VC37 Worcestershire, Southstone Rock | William Charles Richard Watson | William Charles Richard Watson | 28/8/1928 | SLBI |
| Rubus armeniacus | GB, VC16 West Kent, Tunbridge Wells | William Charles Richard Watson | | 20/7/1938 | SLBI |
| Rubus armeniacus | GB, VC16 West Kent, Tunbridge Wells | William Charles Richard Watson | | 20/7/1938 | SLBI |
| Rubus armipotens | GB, VC16 West Kent, Eltham | | William Charles Richard Watson | 28/7/1939 | SLBI |
| Rubus armipotens | GB, VC16 West Kent, Eltham | William Charles Richard Watson | William Charles Richard Watson | 28/7/1939 | SLBI |
| Rubus arrhenii | GB, VC8 South Wiltshire, Longleat Cultivated | William Charles Richard Watson | | 21/7/1954 | SLBI |
| Rubus arrheniiformis | | William Charles Richard Watson | William Charles Richard Watson | 25/7/1948 | SLBI |
| Rubus atrocaulis | GB, VC14 East Sussex, Newbridge | William Charles Richard Watson | William Charles Richard Watson | 17/7/1952 | SLBI |
| Rubus averyanus | GB, VC17 Surrey, Walton Heath | William Charles Richard Watson | William Charles Richard Watson | 7/1944 | SLBI |
| Rubus babingtonianus | GB, VC16 West Kent, Westerham | William Charles Richard Watson | William Charles Richard Watson | 4/7/1947 | SLBI |
| Rubus bakerianus | GB, VC17 Surrey, Putney Heath | William Charles Richard Watson | William Charles Richard Watson | 29/7/1935 | SLBI |
| Rubus bercheriensis | GB, VC16 West Kent, West Wickham | William Charles Richard Watson | William Charles Richard Watson | 12/7/1950 | SLBI |
| Rubus bloxamii | GB, VC16 West Kent, Tunbridge Wells | William Charles Richard Watson | | 8/7/1937 | SLBI |
| Rubus boraeanus | GB, VC18 South Essex, Danbury | William Charles Richard Watson | William Charles Richard Watson | 30/7/1949 | SLBI |
| Rubus boraeanus | GB, VC18 South Essex, Danbury | William Charles Richard Watson | William Charles Richard Watson | 30/7/1949 | SLBI |
| Rubus boraeanus | GB, VC27 East Norfolk, Ringland | William Charles Richard Watson | William Charles Richard Watson | 12/7/1946 | SLBI |
| Rubus botryeros | GB, VC3 South Devon, Hemerdon | | William Charles Richard Watson | 4/7/1937 | SLBI |
| Rubus breconensis | GB, VC35 Monmouthshire, Glanau | William Charles Richard Watson | | 3/9/1952 | SLBI |