| Mentha arvensis x aquatica x spicata = M. x smithiana | GB, VC3 South Devon, Totnes | Francis Morland Day | Job Edward Lousley Arthur Langford Still | 17/9/1938 | SLBI |
| Mentha arvensis x aquatica = M. x verticillata | GB, VC21 Middlesex, Stanmore | Arthur Langford Still | Harold Stuart Thompson | 26/8/1938 | BIRM |
| Mentha aquatica x spicata = M. x piperita | GB, VC6 North Somerset, East Harptree | Arthur Langford Still | | 23/8/1938 | SLBI |
| Mentha arvensis | GB, VC6 North Somerset, East Harptree | Arthur Langford Still | | 23/8/1938 | SLBI |
| Mentha x muelleriana | GB, VC17 Surrey, Wallington Cultivated GB, VC3 South Devon, Salcombe | Arthur Langford Still | Botanical Exchange Club of The British Isles | 15/8/1938 | K |
| Mentha aquatica | GB, VC17 Surrey, Chiddingfold | Arthur Langford Still | | 8/8/1938 | SLBI |
| Mentha arvensis x spicata = M. x gracilis | GB, VC20 Hertfordshire, Harpenden Cultivated | Harry Joseph Riddelsdell | Arthur Langford Still Harry Joseph Riddelsdell | 8/1938 | OXF |
| Carex divisa | GB, VC17 Surrey, Richmond Park | Arthur Langford Still | Arthur Langford Still | 13/6/1938 | SLBI |
| Fumaria bastardii var. hibernica | GB, VC1 West Cornwall, Mullion Cove | Arthur Langford Still | | 12/6/1938 | SLBI |
| Ranunculus parviflorus | GB, VC1 West Cornwall, Mullion | Arthur Langford Still | | 9/6/1938 | SLBI |
| Fumaria occidentalis | GB, VC1 West Cornwall, Lizard | Arthur Langford Still | | 6/1938 | SLBI |
| Mentha piperita var. piperita | GB, VC17 Surrey, Chiddingfold | Arthur Langford Still | Job Edward Lousley | 15/9/1937 | K |
| Mentha suaveolens x longifolia = M. x rotundifolia | GB, VC45 Pembrokeshire, Manorbier | Joseph Donald Grose | Arthur Langford Still | 13/9/1937 | SLBI |
| Mentha spicata x suaveolens = M. x villosa | GB, VC3 South Devon, Dawlish | Arthur Langford Still | University of Exeter | 8/9/1937 | LIV |
| Mentha arvensis x spicata = M. x gracilis | GB, VC17 Surrey, Bookham | Arthur Langford Still | Joseph Norman Frankland | 7/9/1937 | LIV |
| Mentha arvensis x spicata = M. x gracilis | GB, VC23 Oxfordshire, Oxford | | Druce Herbarium, Oxford Arthur Langford Still | 6/9/1937 | OXF |
| Mentha aquatica x spicata = M. x piperita | GB, VC17 Surrey, Chiddingfold | Arthur Langford Still | Job Edward Lousley | 5/9/1937 | CGE |
| Mentha aquatica x spicata = M. x piperita var. citrata | GB, VC17 Surrey, Chiddingfold | Arthur Langford Still | Joseph Norman Frankland | 5/9/1937 | LIV |
| Mentha arvensis x spicata = M. x gracilis | GB, VC41 Glamorganshire, Bishopston | Arthur Langford Still | Botanical Society & Exchange Club of The British Isles Druce Herbarium, Oxford | 3/9/1937 | OXF |
| Mentha gentilis var. vesana | GB, VC41 Glamorganshire, Bishopston | Arthur Langford Still | Botanical Exchange Club of The British Isles | 3/9/1937 | K |
| Mentha aquatica x spicata = M. x piperita | GB, VC41 Glamorganshire, Llangennith,Coity Green | Arthur Langford Still | Job Edward Lousley | 2/9/1937 | SLBI |
| Mentha arvensis x aquatica = M. x verticillata | GB, VC41 Glamorganshire, Parkmill | Arthur Langford Still | Botanical Exchange Club of The British Isles | 1/9/1937 | K |
| Mentha arvensis x spicata = M. x gracilis | GB, VC41 Glamorganshire, Parkmill, Gower | Arthur Langford Still | Botanical Society & Exchange Club of The British Isles Druce Herbarium, Oxford | 1/9/1937 | OXF |
| Mentha x muelleriana | GB, VC17 Surrey, Wallington Cultivated GB, VC3 South Devon, Salcombe | Arthur Langford Still | Botanical Exchange Club of The British Isles | 9/1937 | K |
| Mentha piperita var. piperita | GB, VC33 East Gloucestershire, Fossebridge | Arthur Langford Still | Arthur Langford Still Job Edward Lousley | 23/8/1937 | K |
| Mentha spicata | GB, VC90 Angus, Forfar | Arthur Langford Still | Job Edward Lousley | 21/8/1937 | SLBI |
| Mentha aquatica x spicata = M. x piperita | GB, VC90 Angus, Fern Den | Arthur Langford Still | Job Edward Lousley | 20/8/1937 | SLBI |
| Mentha spicata | GB, VC90 Angus, Edzell,West Water | Arthur Langford Still | Job Edward Lousley | 20/8/1937 | SLBI |
| Mentha longifolia | GB, VC90 Angus, Glamis | Arthur Langford Still | | 19/8/1937 | SLBI |
| Mentha spicata | GB, VC90 Angus, Glamis | Arthur Langford Still | Botanical Exchange Club of The British Isles | 19/8/1937 | K |
| Mentha spicata | GB, VC90 Angus, Glamis | Arthur Langford Still | Botanical Exchange Club of The British Isles | 19/8/1937 | K |
| Mentha suaveolens x longifolia = M. x rotundifolia var. webberi | GB, VC90 Angus, Glamis | Arthur Langford Still Robert Henry Corstorphine | Edward Charles Wallace | 19/8/1937 | OXF |
| Mentha aquatica x spicata = M. x piperita var. crispa | GB, VC17 Surrey, Wallington Cultivated GB, VC70 Cumberland, Carlisle | Arthur Langford Still | Botanical Exchange Club of The British Isles | 10/8/1937 | K |
| Mentha aquatica x spicata = M. x piperita | GB, VC17 Surrey, Wallington Cultivated GB, VC6 North Somerset, Weston in Gordano | Arthur Langford Still | | 8/1937 | OXF |
| Mentha arvensis x spicata = M. x gracilis | GB, VC34 West Gloucestershire, Symonds Yat Cultivated | Arthur Langford Still | | 8/1937 | OXF |
| Mentha arvensis x spicata = M. x gracilis | GB, VC17 Surrey, Wallington Cultivated GB, VC34 West Gloucestershire, Symonds Yat | Arthur Langford Still | Botanical Exchange Club of The British Isles | 8/1937 | K |
| Mentha x piperita | GB, VC17 Surrey, Wallington Cultivated GB, VC6 North Somerset, Weston in Gordano | Arthur Langford Still | Botanical Society & Exchange Club of The British Isles | 8/1937 | K |
| Mentha arvensis x aquatica = M. x verticillata | GB, VC4 North Devon, Belstone | Arthur Langford Still | University of Exeter | 29/7/1937 | LIV |
| Carex divisa | GB, VC17 Surrey, Mitcham Common | Arthur Langford Still | | 3/7/1937 | BM |
| Carex nigra | GB, VC52 Anglesey, Holyhead, Carreg Fawr | Arthur Langford Still | Job Edward Lousley | 7/1937 | SLBI |