+ | Anemone narcissiflora | | | | | MANCH |
+ | Anemone palmata | | | | | MANCH |
+ | Anemone thalictroides | | | | | MANCH |
+ | Anemone vernalis | | | | | MANCH |
| Anisostichus capreolata | US, FL, Bay County, Moccasin Creek | Sidney McDaniel | Florida State University, Robert K. Godfrey Herbarium | 9/4/1966 | FSU |
+ | Annona squamosa | JM, Kingston, St Andrews | | Gilbert McNab John Hutton Balfour | 7/1846 | PTH |
+ | Antennaria triplinervis | | | | 9/1834 | MANCH |
+ | Anthemis arabica | | | | 1833 | MANCH |
+ | Anthemis arvensis subsp. incrassata | FR, Narbonne, Languedoc-Roussillon | Graham | John Hutton Balfour | | PTH |
| Anthemis mixta | GB, VC83 Midlothian, Leith Docks | James Fraser | Allan Octavian Hume | 19/6/1906 | SLBI |
+ | Anthemis nigricans | | | | 1834 | MANCH |
+ | Anthericum liliastrum | | | | | MANCH |
| Anthyllis vulneraria var. dillenii | GB, VC1 West Cornwall, Kynance | Harold Stuart Thompson | Harold Stuart Thompson | 26/8/1886 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC1 West Cornwall, Kynance Cove | William Hadden Beeby | William Hadden Beeby | 20/6/1872 | SLBI |
| Anthyllis vulneraria var. dillenii | GB, VC1 West Cornwall, Kynance Cove | Job Edward Lousley | Harold Stuart Thompson | 25/5/1929 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC1 West Cornwall, Lizard | Harold Stuart Thompson | Harold Stuart Thompson | 7/1888 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC1 West Cornwall, Newquay | Susannah Mary Payne | Augustin Ley | 16/8/1891 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC1 West Cornwall, Portreath | William Curnow | Augustin Ley | 5/1877 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC2 East Cornwall, Bude | Charles Clayton Mountfort | Watson Botanical Exchange Club Augustin Ley E Spearing | 10/6/1908 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC2 East Cornwall, Bude | E West | George Stephen West | 8/1877 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC2 East Cornwall, Whitsand Bay | William Hadden Beeby | William Hadden Beeby | 10/6/1872 | SLBI |
| Anthyllis vulneraria var. maritima | GB, VC16 West Kent, Plumstead | William Henry Griffin | | 13/7/1907 | SLBI |
| Anthyllis vulneraria var. dillenii | GB, VC42 Breconshire, Callwen | Augustin Ley | Augustin Ley | 12/7/1895 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC42 Breconshire, Cwm Haffes | Augustin Ley | Augustin Ley | 10/7/1906 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC45 Pembrokeshire, Stackpole | | Robert Large Baker | 6/1873 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC49 Caernarvonshire, Llanfairfechan | Augustin Ley | Augustin Ley | 18/8/1886 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC49 Caernarvonshire, Traeth Mawr | Augustin Ley | Augustin Ley | 12/8/1886 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC52 Anglesey, Aberffraw | Edward Cleminshaw | Langley Kitching | 1897 | BIRM |
| Anthyllis vulneraria var. dillenii | GB, VC52 Anglesey, Aberffraw | William West | George Stephen West William West | 1/8/1891 | BIRM |
+ | Anthyllis vulneraria subsp. alpestris | CH | | John Hutton Balfour | | PTH |
+ | Apocynum androsaemifolium | | | | 8/7/1834 | MANCH |
+ | Apocynum cannabinum | US, Virginia, Portsmouth | | John Hutton Balfour | | PTH |
+ | Apocynum cannabinum | US, Philadelphia | | Gavin Watson John Hutton Balfour | 7/1845 | PTH |
| Aponogeton distachyos | GB, VC1 West Cornwall, Penryn | Richard Gill | Allan Octavian Hume | 8/4/1910 | SLBI |
| Aponogeton distachyos | GB, VC1 West Cornwall, Tremough | R Gill | The South London Botanical Institute Watson Botanical Exchange Club Harold Stuart Thompson | 8/4/1910 | BIRM |
| Aponogeton distachyos | GB, VC6 North Somerset, Englishcombe | James Walter White | Watson Botanical Exchange Club | 30/5/1924 | SLBI |
| Aponogeton distachyos | GB, VC16 West Kent, Keston | Marjorie Woolley Bostock | | 26/4/1924 | SLBI |
| Aponogeton distachyos | GB, VC16 West Kent, Keston | William Henry Griffin | Allan Octavian Hume | 2/10/1909 | SLBI |
| Aponogeton distachyos | GB, VC83 Midlothian, Edinburgh Royal Botanic Gardens | James Fraser | Allan Octavian Hume | 2/4/1910 | SLBI |
+ | Aquilegia coerulea x vulgaris? | GB, VC88 Mid Perthshire, Finlarig | James Brebner | | 22/7/1881 | PTH |