| Rubus radula | GB, VC17 Surrey, Woking | William Charles Richard Watson | William Charles Richard Watson | 6/8/1938 | SLBI |
| Rubus radula | GB, VC24 Buckinghamshire, Beamond End | William Charles Richard Watson | | 31/7/1950 | SLBI |
| Rubus questieri | GB, VC9 Dorset, Foxholes Wood | William Charles Richard Watson | William Charles Richard Watson | 2/7/1951 | SLBI |
| Rubus pyramidalis | GB, VC39 Staffordshire, Stowe, Hand Leasow Wood | Eric Smoothy Edees | William Charles Richard Watson | 28/7/1952 | SLBI |
| Rubus putneiensis | GB, VC17 Surrey, Putney Heath Cultivated | William Charles Richard Watson | | 28/6/1943 | SLBI |
| Rubus pullifolius | GB, VC9 Dorset, Bournemouth | William Charles Richard Watson | William Charles Richard Watson | 1/7/1951 | SLBI |
| Rubus pullifolius | GB, VC9 Dorset, Talbot Heath | William Charles Richard Watson | William Charles Richard Watson | 1/7/1951 | SLBI |
| Rubus pruinosus | IE, VCH39 Co. Antrim, Drumnadarragh | John Patrick Micklethwait Brenan Norman Douglas Simpson | William Charles Richard Watson | 17/8/1939 | SLBI |
| Rubus prolongatus | GB, VC36 Herefordshire, Lyonshall | William Charles Richard Watson | William Charles Richard Watson | 20/8/1928 | SLBI |
| Rubus prolongatus | GB, VC36 Herefordshire, Lyonshall | William Charles Richard Watson | William Charles Richard Watson | 20/8/1928 | SLBI |
| Rubus proiectus | GB, VC16 West Kent, Tunbridge Wells | William Charles Richard Watson | William Charles Richard Watson | 11/8/1945 | SLBI |
| Rubus proiectus | GB, VC16 West Kent, Tunbridge Wells | William Charles Richard Watson | William Charles Richard Watson | 11/8/1945 | SLBI |
| Rubus praetextus | GB, VC16 West Kent, Hosey Common | William Charles Richard Watson | | | SLBI |
| Rubus praetextus | GB, VC16 West Kent, Hosey Common | William Charles Richard Watson | William Charles Richard Watson | | SLBI |
| Rubus powellii | GB, VC18 South Essex, Epping Forest | William Charles Richard Watson | | 21/7/1928 | SLBI |
| Rubus polyanthemus | GB, VC17 Surrey, Wisley | William Charles Richard Watson | | 13/7/1949 | SLBI |
| Rubus poliodes | GB, VC24 Buckinghamshire, Brickhill | William Charles Richard Watson | William Charles Richard Watson | 30/7/1946 | SLBI |
| Rubus plicatus | GB, VC16 West Kent, Tunbridge Wells | William Charles Richard Watson | William Charles Richard Watson | 10/7/1937 | SLBI |
| Rubus plicatus | GB, VC30 Bedfordshire, Heath and Reach | William Charles Richard Watson | William Charles Richard Watson | 30/7/1946 | SLBI |
| Rubus platyacanthus | GB, VC16 West Kent, Hayes Common | William Charles Richard Watson | W O R Watson | 2/7/1937 | SLBI |
| Rubus platyacanthus | GB, VC36 Herefordshire, Coughton | William Charles Richard Watson | William Charles Richard Watson | 21/7/1932 | SLBI |
| Rubus pictorum | GB, VC87 West Perthshire, Doune | William Hobson Mills | William Charles Richard Watson | 21/7/1953 | SLBI |
| Rubus phaeocarpus | GB, VC17 Surrey, Roehampton | William Charles Richard Watson | William Charles Richard Watson | 30/8/1928 | SLBI |
| Rubus peninsulae | GB, VC2 East Cornwall, Restormel Cultivated | William Charles Richard Watson | | 28/7/1954 | SLBI |
| Rubus pedemontanus | GB, VC55 Leicestershire, Bloody Oak Wood | William Charles Richard Watson | William Charles Richard Watson | 20/6/1948 | SLBI |
| Rubus pedemontanus | GB, VC55 Leicestershire, Bloody Oaks Wood | William Charles Richard Watson | | 20/6/1948 | SLBI |
| Rubus patuliformis | GB, VC16 West Kent, Rusthall Common | William Charles Richard Watson | William Charles Richard Watson | 7/9/1950 | SLBI |
| Rubus pascuorum | GB, VC16 West Kent, Selsdon | Eric Smoothy Edees | William Charles Richard Watson | 19/7/1952 | SLBI |
| Rubus pampinosus | GB, VC40 Shropshire | William Charles Richard Watson | William Charles Richard Watson | 15/7/1953 | SLBI |
| Rubus pallidus | GB, VC16 West Kent, Bostall Heath | William Charles Richard Watson | | 16/7/1931 | SLBI |
| Rubus pallidus | GB, VC62 North-east Yorkshire, Pilmoor | Catherine Muriel Rob | William Charles Richard Watson | 21/7/1947 | SLBI |
| Rubus pallidisetus | GB, VC34 West Gloucestershire, Mitcheldean Meend | William Charles Richard Watson | | 19/7/1932 | SLBI |
| Rubus pallidisetus | GB, VC34 West Gloucestershire, Mitcheldean Meend | William Charles Richard Watson | William Charles Richard Watson | 19/7/1932 | SLBI |
| Rubus oxyanchus | GB, VC17 Surrey, Newlands Corner | William Charles Richard Watson | William Charles Richard Watson | 27/6/1937 | SLBI |
| Rubus oxyanchus | GB, VC17 Surrey, Newlands Corner | William Charles Richard Watson | | 27/6/1937 | SLBI |
| Rubus orbus | GB, VC3 South Devon, near Cholwicktown | William Charles Richard Watson | William Charles Richard Watson | 6/7/1917 | SLBI |
| Rubus opacus | GB, VC39 Staffordshire, Stowe, Hand Leasow Wood | Eric Smoothy Edees | William Charles Richard Watson | 28/7/1952 | SLBI |
| Rubus opacus | GB, VC39 Staffordshire, Stowe, Hand Leasow Wood | Eric Smoothy Edees | William Charles Richard Watson | 28/7/1952 | SLBI |
| Rubus nobilissimus | GB, VC17 Surrey, Littleworth Common, Esher | William Charles Richard Watson | William Charles Richard Watson | 8/7/1947 | SLBI |
| Rubus nobilissimus | GB, VC17 Surrey, Littleworth Common, Esher | William Charles Richard Watson | William Charles Richard Watson | 8/7/1947 | SLBI |