| Mentha arvensis x aquatica = M. x verticillata | GB, VC19 North Essex, Tiptree Heath | George Charles Brown | Botanical Society & Exchange Club of The British Isles | 1/9/1912 | CGE |
| Mentha arvensis x aquatica = M. x verticillata | GB, VC19 North Essex, Fingringhoe | George Charles Brown | Botanical Exchange Club of The British Isles George Charles Brown Job Edward Lousley | 12/8/1926 | SLBI |
| Mentha arvensis x aquatica x spicata = M. x smithiana | GB, VC19 North Essex, Mersea Island | George Charles Brown | | 9/1912 | CGE |
| Mentha arvensis x aquatica x spicata = M. x smithiana | GB, VC19 North Essex, Alphamstone | George Charles Brown | Richard Barker Ullman | 26/8/1928 | SLBI |
| Mentha arvensis x aquatica x spicata = M. x smithiana | GB, VC19 North Essex, Alphamstone | George Charles Brown | Botanical Exchange Club of The British Isles George Charles Brown Job Edward Lousley | 26/8/1928 | SLBI |
| Mentha arvensis x aquatica x spicata = M. x smithiana | GB, VC19 North Essex, Alphamstone | George Charles Brown | Botanical Society & Exchange Club of The British Isles George Charles Brown | 26/8/1928 | K |
| Mentha arvensis x spicata = M. x gracilis | GB, VC19 North Essex, Alphamstone Cultivated | George Charles Brown | George Claridge Druce | 1/9/1920 | OXF |
| Mentha arvensis x spicata = M. x gracilis | GB, VC19 North Essex, Alphamstone Cultivated | George Charles Brown | Druce Herbarium, Oxford J Fraser | 7/9/1916 | OXF |
| Mentha longifolia | GB, VC26 West Suffolk, Nayland | George Charles Brown | Botanical Exchange Club of The British Isles George Charles Brown Job Edward Lousley | 9/9/1926 | SLBI |
| Mentha piperita var. piperita | GB, VC19 North Essex, Colchester, Middlewick Rifle Ranges | George Charles Brown | Botanical Society & Exchange Club of The British Isles George Charles Brown J Fraser | 9/8/1925 16/8/1925 | K |
| Mentha spicata | GB, VC26 West Suffolk, Nayland | George Charles Brown | Botanical Exchange Club of The British Isles Charles Edward Britton George Charles Brown | | K |
| Mentha spicata x suaveolens = M. x villosa var. alopecuroides | GB, VC19 North Essex, West Bergholt | George Charles Brown | Botanical Exchange Club of The British Isles George Charles Brown | 10/9/1931 | K |
| Mentha spicata x suaveolens = M. x villosa | GB, VC19 North Essex, West Bergholt | George Charles Brown | Botanical Society & Exchange Club of The British Isles George Charles Brown Job Edward Lousley | 10/9/1931 | SLBI |
| Mentha spicata x suaveolens = M. x villosa var. alopecuroides | GB, VC19 North Essex, West Bergholt | George Charles Brown | George Charles Brown J Fraser | 10/9/1931 | K |
| Myosurus minimus | GB, VC19 North Essex, Birch | George Charles Brown | William Robert Sherrin | 8/6/1911 | SLBI |
| Plantago coronopus | GB, VC19 North Essex, Colchester,Hythe Quay | Charles Edward Britton George Charles Brown | Botanical Exchange Club of The British Isles George Charles Brown | 27/9/1928 | K |
| Plantago coronopus | GB, VC19 North Essex, Colchester,Hythe Quay | George Charles Brown | Botanical Society & Exchange Club of The British Isles George Charles Brown | 27/9/1928 | K |
| Polygonum cognatum | GB, VC19 North Essex, Colchester | George Charles Brown | Botanical Exchange Club of The British Isles Richard Barker Ullman Patrick Martin Hall | 22/7/1928 | SLBI |
| Populus balsamifera x deltoides = P. x jackii | GB, VC26 West Suffolk, Brent Eleigh | George Charles Brown | Douglas Montague Heath Frederick Robinson | 19/8/1915 | BIRM |
| Potamogeton lucens | VC26, Wiston | George Charles Brown | | 8/6/1919 | SLBI |
| Potamogeton polygonifolius | GB, VC19 North Essex, Tiptree Heath | George Charles Brown | Botanical Society & Exchange Club of The British Isles | 6/5/1920 | MANCH |
| Potamogeton polygonifolius | GB, VC19 North Essex, Tiptree Heath | George Charles Brown | Botanical Exchange Club of The British Isles | 16/5/1920 | E |
| Potentilla erecta x anglica = P. x suberecta | GB, VC19 North Essex, Henny | George Charles Brown | Botanical Society & Exchange Club of The British Isles Charles Bailey | 4/7/1915 | MANCH |
| Potentilla erecta x anglica = P. x suberecta | GB, VC19 North Essex, Tiptree Heath | George Charles Brown | Job Edward Lousley | 3/6/1926 | SLBI |
+ | Primula elatior | GB, VC19 North Essex, Essex, Hatfield-Broad-Oak, Hatfield Forest | George Charles Brown | Frederick Ernest Weiss | 13/4/1925 | MANCH |
| Rosa rubiginosa | GB, VC19 North Essex, Tiptree Heath | George Charles Brown | Botanical Exchange Club of The British Isles | 18/7/1937 | SLBI |
| Rubus angusticuspis | GB, VC18 South Essex, Danbury | George Charles Brown | Botanical Exchange Club of The British Isles George Charles Brown | 7/7/1934 | SLBI |
| Rubus anisacanthos | GB, VC19 North Essex, Berechurch | George Charles Brown | | 15/7/1934 | SLBI |
| Rubus anisacanthos | GB, VC19 North Essex, Berechurch | George Charles Brown | Botanical Exchange Club of The British Isles George Charles Brown | 15/7/1934 | SLBI |
| Rubus anisacanthos | GB, VC19 North Essex, East Donyland | George Charles Brown | Botanical Exchange Club of The British Isles | 8/7/1936 | SLBI |
| Rubus anisacanthos | GB, VC19 North Essex, East Donyland | George Charles Brown | Botanical Society & Exchange Club of The British Isles George Charles Brown | 8/7/1936 | SLBI |
| Rubus corylifolius | GB, VC19 North Essex, Colchester | George Charles Brown | Botanical Exchange Club of The British Isles | 22/7/1923 | SLBI |
| Rubus criniger | GB, VC19 North Essex, Berechurch | George Charles Brown | George Charles Brown | 29/7/1935 | SLBI |
| Rubus criniger | GB, VC18 South Essex, Danbury | George Charles Brown | George Charles Brown | 7/7/1934 | SLBI |
| Rubus criniger | GB, VC18 South Essex, Danbury | George Charles Brown | Watson Botanical Exchange Club George Charles Brown | 7/7/1934 | SLBI |
| Rubus criniger | GB, VC19 North Essex, Stanway | George Charles Brown | Botanical Exchange Club of The British Isles | 17/7/1923 | SLBI |
| Rubus criniger | GB, VC19 North Essex, Layer de la Haye | George Charles Brown | Botanical Society & Exchange Club of The British Isles George Charles Brown | 10/7/1938 | SLBI |
| Rubus criniger | GB, VC19 North Essex, Stanway | George Charles Brown | | 19/7/1923 | SLBI |
| Rubus dasyphyllus | GB, VC19 North Essex, Berechurch | George Charles Brown | Botanical Exchange Club of The British Isles | 31/7/1934 | SLBI |
| Rubus dasyphyllus | GB, VC19 North Essex, Berechurch | George Charles Brown | Botanical Exchange Club of The British Isles | 31/7/1934 | SLBI |