| Groenlandia densa | GB, VC54 North Lincolnshire, Haxey | Cecil Ivry Sandwith Noel Yvri Sandwith | | 8/1939 | K |
| Herminium monorchis | GB, VC17 Surrey, Box Hill | Herbert Kenneth Airy Shaw Noel Yvri Sandwith Thomas Archibald Sprague | | 14/6/1927 | K |
| Hypochaeris glabra | GB, VC56 Nottinghamshire, Everton | Cecil Ivry Sandwith Noel Yvri Sandwith | | 9/8/1939 | K |
| Hypochaeris radicata x glabra = H. x intermedia | GB, VC17 Surrey, Wonersh | Noel Yvri Sandwith | | 22/8/1953 | K |
| Hypochaeris radicata x glabra = H. x intermedia | GB, VC17 Surrey, Wonersh | Noel Yvri Sandwith | | 16/8/1953 | K |
| Hypochaeris radicata x glabra = H. x intermedia | GB, VC17 Surrey, Wonersh | Noel Yvri Sandwith | | 16/8/1953 | K |
| Hypochaeris radicata x glabra = H. x intermedia | GB, VC17 Surrey, Wonersh | Edward Charles Wallace Noel Yvri Sandwith | | 16/8/1953 | K |
| Juncus subnodulosus | GB, VC6 North Somerset, Nailsea | Harold Stuart Thompson Noel Yvri Sandwith | Harold Stuart Thompson | 10/9/1921 | BIRM |
| Kickxia spuria | GB, VC11 South Hampshire, Hayling Island | Cecil Ivry Sandwith Noel Yvri Sandwith | | 11/9/1927 | K |
| Lamium confertum | GB, VC94 Banffshire, Cullen | Cecil Ivry Sandwith Noel Yvri Sandwith | | 22/7/1938 | K |
| Lamium galeobdolon subsp. montanum | GB, VC17 Surrey, Bletchingley | Noel Yvri Sandwith | | 30/5/1942 | K |
| Lamium galeobdolon subsp. montanum | GB, VC17 Surrey, Headley | Noel Yvri Sandwith | | 25/5/1946 | K |
| Lamium galeobdolon subsp. montanum | GB, VC24 Buckinghamshire, Bradenham | Noel Yvri Sandwith | | 30/5/1931 | K |
| Lamium galeobdolon subsp. montanum | GB, VC24 Buckinghamshire, Bradenham | Noel Yvri Sandwith | Noel Yvri Sandwith | 30/5/1931 | K |
| Lamium galeobdolon subsp. montanum | GB, VC17 Surrey, Kew Gardens Cultivated GB, VC24 Buckinghamshire, Bradenham | Noel Yvri Sandwith | | 9/5/1933 | K |
| Lamium maculatum | GB, VC50 Denbighshire, Llanshaiads | Noel Yvri Sandwith | Noel Yvri Sandwith | 8/7/1942 | K |
| Lamium purpureum var. hybridum | GB, VC22 Berkshire, Aldermaston | Noel Yvri Sandwith | | 13/5/1956 | K |
| Lamium purpureum var. hybridum | GB, VC54 North Lincolnshire, Epworth | Noel Yvri Sandwith | | 13/8/1939 | K |
| Lepidium graminifolium | GB, VC34 West Gloucestershire, Avonmouth Docks, Bristol | James Walter White Noel Yvri Sandwith | Watson Botanical Exchange Club James Walter White | 27/10/1925 | SLBI |
| Lepidium perfoliatum | GB, VC34 West Gloucestershire, Ashton Gate | Cecil Ivry Sandwith Noel Yvri Sandwith | Harold Stuart Thompson | 5/6/1918 | BIRM |
| Ligustrum vulgare | GB, VC6 North Somerset, Cleeve Toot | Cecil Ivry Sandwith Noel Yvri Sandwith | | 29/12/1945 | K |
| Linaria genistifolia subsp. chloraefolia | GB, VC34 West Gloucestershire, Avonmouth Docks, Bristol | Noel Yvri Sandwith | | 16/9/1933 | K |
| Linaria repens | GB, VC34 West Gloucestershire, Avonmouth | Cecil Ivry Sandwith Noel Yvri Sandwith | | 21/8/1949 | K |
| Linaria repens | GB, VC34 West Gloucestershire, Chittening Warth | Cecil Ivry Sandwith Noel Yvri Sandwith | | 12/8/1956 | K |
| Linaria repens | GB, VC42 Breconshire, Trecastle | Arthur Hugh Garfit Alston Noel Yvri Sandwith | | 4/9/1932 | K |
| Linaria vulgaris | GB, VC34 West Gloucestershire, Avonmouth Docks, Bristol | Cecil Ivry Sandwith Noel Yvri Sandwith | | 9/1935 | K |
| Linaria vulgaris | GB, VC34 West Gloucestershire, Avonmouth Docks, Bristol | Cecil Ivry Sandwith Noel Yvri Sandwith | | 9/1935 | K |
| Linaria vulgaris x repens = L. x sepium | GB, VC14 East Sussex, Lewes | Cecil Ivry Sandwith Noel Yvri Sandwith | | 24/8/1930 | K |
| Linaria vulgaris x repens = L. x sepium | GB, VC34 West Gloucestershire, Avonmouth | Cecil Ivry Sandwith Noel Yvri Sandwith | | 12/8/1956 | K |
| Lolium multiflorum | GB, VC34 West Gloucestershire, Eastville, Bristol | N Sandwith Noel Yvri Sandwith | Harold Stuart Thompson | 26/7/1917 | BIRM |
| Marrubium vulgare | GB, VC31 Huntingdonshire, Conington | John Lester Gilbert Noel Yvri Sandwith | | 21/9/1957 | K |
| Mentha aquatica | GB, VC17 Surrey, Cut Mill Pond | J Fraser Noel Yvri Sandwith | | 21/8/1927 | K |
| Mentha aquatica | GB, VC17 Surrey, Richmond Park | Arthur Keith Jackson Cecil Victor Boley Marquand Herbert Kenneth Airy Shaw Noel Yvri Sandwith | | 14/9/1934 | K |
| Mentha aquatica | GB, VC17 Surrey, Richmond Park, Pen Pond | Edgar Wolston Bertram Handsley Milne-Redhead Noel Yvri Sandwith | | 14/9/1934 | K |
| Mentha aquatica x spicata = M. x piperita | GB, VC46 Cardiganshire, Mount | Cecil Ivry Sandwith Noel Yvri Sandwith | | 9/1932 | K |
| Mentha arvensis | GB, VC6 North Somerset, Cranmore | Cecil Ivry Sandwith Noel Yvri Sandwith | | 30/7/1941 | K |
| Mentha arvensis var. densifoliata | GB, VC6 North Somerset, Glastonbury | Noel Yvri Sandwith | | 13/9/1933 | K |
| Mentha arvensis | GB, VC17 Surrey, Coombe | Noel Yvri Sandwith | Noel Yvri Sandwith | 3/10/1942 | K |
| Mentha arvensis x aquatica = M. x verticillata | GB, VC17 Surrey, Richmond Park, Pen Pond | Edgar Wolston Bertram Handsley Milne-Redhead Noel Yvri Sandwith | | 14/9/1934 | K |
| Mentha arvensis x aquatica = M. x verticillata | GB, VC17 Surrey, Wisley | J Fraser Noel Yvri Sandwith | | 21/8/1927 | K |