| Potamogeton obtusifolius | GB, VC37 Worcestershire, Trimpley | Joseph Hesselgrave Thompson | | 9/8/1883 | ABS |
| Potamogeton natans | GB, VC37 Worcestershire, Hartlebury | Joseph Hesselgrave Thompson | William Hunt Painter | 13/4/1848 | ABS |
| Potamogeton compressus | GB, VC37 Worcestershire, Hartlebury Common | Joseph Hesselgrave Thompson | | 8/1871 | ABS |
| Polypogon monspeliensis | GB, VC37 Worcestershire, Kidderminster | Joseph Hesselgrave Thompson | | 9/1875 | ABS |
| Polypogon monspeliensis | GB, VC37 Worcestershire, Kidderminster | Joseph Hesselgrave Thompson | | 4/9/1875 | ABS |
| Polygonum aviculare | GB, VC37 Worcestershire, Droitwich | Joseph Hesselgrave Thompson | Donor Unknown | 8/11/1852 | BIRM |
| Polygala serpyllifolia | GB, VC38 Warwickshire, Sutton Park | Joseph Hesselgrave Thompson | | 16/6/1877 | ABS |
| Polygala serpyllifolia | GB, VC38 Warwickshire, Sutton Park | Joseph Hesselgrave Thompson | | 16/6/1877 | BIRM |
| Polygala calcarea | GB, VC22 Berkshire, Pangbourne | Joseph Hesselgrave Thompson | William Hunt Painter | 28/5/1881 | ABS |
| Poa nemoralis | GB, VC37 Worcestershire, Fenny Rough | Frederick Arnold Lees John Fraser Joseph Hesselgrave Thompson | William Hunt Painter | 2/6/1883 | ABS |
| Poa compressa subsp. polynoda | GB, VC37 Worcestershire, Bewdley | Joseph Hesselgrave Thompson | William Hunt Painter | 24/7/1882 | ABS |
| Poa compressa | GB, VC36 Herefordshire, Ledbury | Joseph Hesselgrave Thompson | William Hunt Painter | 21/7/1884 | ABS |
| Pilosella aurantiaca | GB, VC37 Worcestershire, Tenbury | Joseph Hesselgrave Thompson | William Hunt Painter | 6/1878 | ABS |
| Pilosella aurantiaca | GB, VC37 Worcestershire, Tenbury | Joseph Hesselgrave Thompson | | 21/6/1878 | ABS |
| Petasites hybridus | GB, VC37 Worcestershire, Cradley | Joseph Hesselgrave Thompson | | 10/4/1884 | ABS |
| Pastinaca sativa | GB, VC40 Shropshire, Highley | Joseph Hesselgrave Thompson | William Hunt Painter | 28/7/1881 | ABS |
| Parietaria judaica | GB, VC41 Glamorganshire, Llandaff | Joseph Hesselgrave Thompson | Donor Unknown Martha Maria Atwood | 9/6/1853 | BIRM |
| Parapholis strigosa | GB, VC9 Dorset, Chesil Bank | Joseph Hesselgrave Thompson | William Hunt Painter | 20/8/1857 | ABS |
| Ornithogalum nutans | GB, VC37 Worcestershire, Charlton | Joseph Hesselgrave Thompson | William Hunt Painter | 2/5/1879 | ABS |
| Ornithogalum nutans | GB, VC37 Worcestershire, Hartlebury | Joseph Hesselgrave Thompson | William Hunt Painter | 4/1878 | ABS |
| Oreopteris limbosperma | AT, Gastein | Joseph Hesselgrave Thompson | William Hunt Painter | 9/1879 | ABS |
| Ophrys apifera | GB, VC40 Shropshire, Highley | Joseph Hesselgrave Thompson | | 29/6/1882 | ABS |
| Neckeria lutea | GB, VC37 Worcestershire, Malvern Wells | Joseph Hesselgrave Thompson | William Hunt Painter | 8/1878 | ABS |
| Nasturtium sylvestre | GB, VC37 Worcestershire, Bewdley | Joseph Hesselgrave Thompson | Croydon Natural History and Scientific Society John Joseph Bennett Robert Russell Hutchinson | | SLBI |
| Myrica gale | GB, VC17 Surrey, Farnham | Joseph Hesselgrave Thompson | Donor Unknown Martha Maria Atwood | 1850 | BIRM |
| Myrica gale | GB, VC86,VC99, Rowardennan | Joseph Hesselgrave Thompson | Donor Unknown Martha Maria Atwood | 2/7/1844 | BIRM |
| Myosurus minimus | GB, VC37 Worcestershire, Porter's Mill | Joseph Hesselgrave Thompson | | 1852 | BIRM |
| Myosotis sylvatica | GB, VC37 Worcestershire, Bredon | Joseph Hesselgrave Thompson | William Hunt Painter | 20/5/1851 | ABS |
| Myosotis sylvatica | GB, VC56 Nottinghamshire, Clifton Grove | Joseph Hesselgrave Thompson | William Hunt Painter | | ABS |
| Myosotis discolor | GB, VC37 Worcestershire, Kidderminster | Joseph Hesselgrave Thompson | William Hunt Painter | 29/4/1876 | ABS |
| Misopates orontium | GB, VC37 Worcestershire, Worcester | Joseph Hesselgrave Thompson | William Hunt Painter | 24/9/1857 | ABS |
| Mimulus guttatus | GB, VC37 Worcestershire, Churchill | Joseph Hesselgrave Thompson | William Hunt Painter | 10/7/1877 | ABS |
| Menyanthes trifoliata | GB, VC37 Worcestershire, Hartlebury | Joseph Hesselgrave Thompson | William Hunt Painter | 29/5/1852 | ABS |
| Mentha arvensis x spicata = M. x gracilis | GB, VC38 Warwickshire, Arley | Joseph Hesselgrave Thompson | William Hunt Painter | 9/1878 | ABS |
| Mentha aquatica x spicata = M. x piperita | GB, VC37 Worcestershire, Saint George's, Worcester | Joseph Hesselgrave Thompson | William Hunt Painter | 1/8/1846 | ABS |
| Melittis melissophyllum | GB, VC3 South Devon, Torquay | Joseph Hesselgrave Thompson | | 29/6/1853 | ABS |
| Melilotus indicus | GB, VC39 Staffordshire, Wolverhampton | | J Fraser Joseph Hesselgrave Thompson William Hunt Painter | 22/9/1873 | ABS |
| Melilotus albus | GB, VC37 Worcestershire, Pedmore | Joseph Hesselgrave Thompson | William Hunt Painter | 18/8/1876 | ABS |
| Melica nutans | GB, VC36 Herefordshire, Doward hill | Joseph Hesselgrave Thompson | William Hunt Painter | 31/5/1851 | ABS |
| Melampyrum pratense | GB, VC35 Monmouthshire, Wynd Cliff | Joseph Hesselgrave Thompson | William Hunt Painter | 5/1881 | ABS |