| Scleranthus annuus | IE, VCH38 Co. Down, grey abbey | Coslett Herbert Waddell | Watson Botanical Exchange Club Coslett Herbert Waddell Harold Stuart Thompson | 2/10/1917 | BIRM |
| Barbarea intermedia | IE, VCH38 Co. Down, Greyabbey | Coslett Herbert Waddell | Botanical Exchange Club of The British Isles Coslett Herbert Waddell Douglas Montague Heath Frederick Robinson | 6/1917 | BIRM |
| Polygonum arenastrum | IE, VCH38 Co. Down, Greyabbey | Coslett Herbert Waddell | Watson Botanical Exchange Club Coslett Herbert Waddell Harold Stuart Thompson | 9/1916 | BIRM |
| Polygonum rurivagum | IE, VCH38 Co. Down, Greyabbey | Coslett Herbert Waddell | Watson Botanical Exchange Club Coslett Herbert Waddell Harold Stuart Thompson | 9/1916 | BIRM |
| Atriplex glabriuscula | IE, VCH38 Co. Down, Groomsport | Coslett Herbert Waddell | Watson Botanical Exchange Club Edward Cleminshaw | 9/1897 | BIRM |
| Atriplex patula | IE, VCH38 Co. Down, Killough | Coslett Herbert Waddell | Watson Botanical Exchange Club Coslett Herbert Waddell Harold Stuart Thompson | 8/1897 | BIRM |
| Apium inundatum | IE, VCH38 Co. Down, Kircubbin | Coslett Herbert Waddell | Watson Botanical Exchange Club Harold Stuart Thompson | 1918 | BIRM |
| Apium inundatum | IE, VCH38 Co. Down, Kircubbin | Coslett Herbert Waddell | Watson Botanical Exchange Club Harold Stuart Thompson | 1918 | BIRM |
| Eleogiton fluitans | IE, VCH38 Co. Down, Kircubbin | Coslett Herbert Waddell | Coslett Herbert Waddell Harold Stuart Thompson Watson Botanical Exchange Club | 7/1918 | BIRM |
| Euphrasia nemorosa | IE, VCH38 Co. Down, Mount Stewart | Coslett Herbert Waddell | Watson Botanical Exchange Club Harold Stuart Thompson | 1916 | BIRM |
| Mentha spicata | IE, VCH38 Co. Down, Saintfield Cultivated | Coslett Herbert Waddell | Watson Botanical Exchange Club Augustin Ley Coslett Herbert Waddell | 7/1902 | BIRM |
| Salix daphnoides | IE, VCH38 Co. Down, Saintfield | Coslett Herbert Waddell | Botanical Exchange Club of The British Isles Augustin Ley Coslett Herbert Waddell | 4/1909 to 8/1909 | BIRM |
| Ranunculus peltatus | IE, VCH38 Co. Down, Saintfield | Coslett Herbert Waddell | Watson Botanical Exchange Club Augustin Ley Coslett Herbert Waddell | 30/6/1909 | BIRM |
| Polygonum aviculare | IE, VCH38 Co. Down, Saintfield | Coslett Herbert Waddell | Watson Botanical Exchange Club Augustin Ley Coslett Herbert Waddell | 8/1909 | BIRM |
| Viola tricolor subsp. saxatilis | IE, VCH38 Co. Down, Saintfield | Coslett Herbert Waddell | Watson Botanical Exchange Club Augustin Ley Coslett Herbert Waddell | 4/10/1910 | BIRM |
| Circaea lutetiana x alpina = C. x intermedia | IE, VCH38 Co. Down, Saintfield | Coslett Herbert Waddell | Watson Botanical Exchange Club Coslett Herbert Waddell Harold Stuart Thompson | | BIRM |
| Valeriana officinalis | IE, VCH38 Co. Down, Saintfield | Coslett Herbert Waddell | Coslett Herbert Waddell Harold Stuart Thompson | 8/1895 | BIRM |
| Potamogeton obtusifolius | IE, VCH38 Co. Down, Saintfield | Coslett Herbert Waddell | Coslett Herbert Waddell Harold Stuart Thompson | 9/1896 | BIRM |
| Equisetum pratense | IE, VCH39 Co. Antrim, Belfast | Coslett Herbert Waddell | Watson Botanical Exchange Club Coslett Herbert Waddell Harold Stuart Thompson | 5/1901 | BIRM |
| Rosa sherardii | IE, VCH39 Co. Antrim, Carnlough | Coslett Herbert Waddell | Botanical Exchange Club of The British Isles Coslett Herbert Waddell | 9/8/1910 | BIRM |
| Callitriche autumnalis | IE, VCH39 Co. Antrim, Lough Neagh | Coslett Herbert Waddell | Watson Botanical Exchange Club Augustin Ley Coslett Herbert Waddell | 13/8/1909 | BIRM |
| Mentha spicata x suaveolens = M. x villosa | IE, VCH38 Co. Down, Saul | Coslett Herbert Waddell | Coslett Herbert Waddell | 2/10/1894 | CGE |
| Mentha aquatica x spicata = M. x piperita | IE, VCH39 Co. Antrim, Carnmoney | Coslett Herbert Waddell | Watson Botanical Exchange Club Coslett Herbert Waddell Spencer Henry Bickham | 8/1895 | CGE |
| Mentha arvensis x aquatica x spicata = M. x smithiana | IE, VCH38 Co. Down, Saintfield Cultivated | Coslett Herbert Waddell | Coslett Herbert Waddell | 9/1894 | DBN |
| Mentha spicata x suaveolens = M. x villosa | IE, VCH38 Co. Down, Saul Cultivated | Coslett Herbert Waddell | Coslett Herbert Waddell Robert Lloyd Praeger | 9/1894 | DBN |
| Mentha spicata x suaveolens = M. x villosa | IE, VCH38 Co. Down, Saul | Coslett Herbert Waddell | Coslett Herbert Waddell | 9/1894 | DBN |
| Mentha spicata x suaveolens = M. x villosa | IE, VCH38 Co. Down, Saul Cultivated | Coslett Herbert Waddell | Alexander Goodman More Coslett Herbert Waddell | 21/9/1894 | DBN |
| Mentha spicata x suaveolens = M. x villosa | IE, VCH38 Co. Down, Saul | Coslett Herbert Waddell | National Museum Ireland Alexander Goodman More Coslett Herbert Waddell | 2/10/1894 | DBN |
| Mentha spicata x suaveolens = M. x villosa | IE, VCH38 Co. Down, Saul | Coslett Herbert Waddell | Alexander Goodman More Coslett Herbert Waddell | 2/10/1894 | DBN |
| Mentha aquatica x spicata = M. x piperita | IE, VCH38 Co. Down, Saul | Coslett Herbert Waddell | Alexander Goodman More Coslett Herbert Waddell | 2/10/1894 | DBN |
| Mentha aquatica x spicata = M. x piperita | IE, VCH38 Co. Down, Saul | Coslett Herbert Waddell | | 2/10/1894 | DBN |
| Mentha spicata x suaveolens = M. x villosa | IE, VCH38 Co. Down, Saul | Coslett Herbert Waddell | | 2/10/1894 | DBN |
| Mentha spicata x suaveolens = M. x villosa | IE, VCH38 Co. Down, Saul Cultivated | Coslett Herbert Waddell | | 9/1895 | DBN |
| Myosotis ramosissima | IE, VCH38 Co. Down, Kirkistown | Coslett Herbert Waddell | Belfast | 5/1894 | GALW |
| Linum catharticum | IE, VCH38 Co. Down, Saintfield | | Coslett Herbert Waddell | 7/1916 | GALW |
| Leonurus cardiaca | GB, VC54 North Lincolnshire, Ingoldmells | Helen M Nash | Coslett Herbert Waddell | 11/9/1913 | K |
| Pyrola media | IE, VCH36 Tyrone, Kildress | Samuel Arthur Brennan | Watson Botanical Exchange Club Coslett Herbert Waddell | 7/1897 | K |
| Callitriche intermedia | IE, VCH38 Co. Down, Aughnadarragh | Coslett Herbert Waddell | Coslett Herbert Waddell John Innes Horticultural Institute | 8/1896 | K |
| Callitriche obtusangula | IE, VCH38 Co. Down, Belfast Harbour | | Coslett Herbert Waddell John Innes Horticultural Institute | 7/1904 | K |
| Thymus praecox subsp. arcticus | IE, VCH38 Co. Down, Orlock Point | Coslett Herbert Waddell | Watson Botanical Exchange Club Albert Bruce Jackson Coslett Herbert Waddell | 8/1909 | K |