| Potamogeton alpinus | IE, VCH38 Co. Down, Newcastle | Samuel Alexander Stewart | Alfred Fryer Charles Bailey | 8/8/1890 | MANCH |
+ | Galeopsis versicolor | IE, VCH38 Co. Down, Rathmullan | Samuel Alexander Stewart | Charles Bailey James Ward | 26/7/1866 | MANCH |
| Mentha arvensis x aquatica = M. x verticillata | IE, VCH38 Co. Down, Saul | Samuel Alexander Stewart | | 8/1897 | DBN |
| Viola tricolor subsp. curtisii | IE, VCH39 Co. Antrim, Antrim | Samuel Alexander Stewart | Botanical Exchange Club of The British Isles William Hadden Beeby John Gilbert Baker | 25/6/1886 | SLBI |
| Potamogeton alpinus | IE, VCH39 Co. Antrim, Belfast | Samuel Alexander Stewart | Richmond Museum Charles Bailey James Ward | 2/7/1866 | MANCH |
| Potentilla anglica | IE, VCH39 Co. Antrim, Belfast | Samuel Alexander Stewart | | 7/1893 | SLBI |
| Rosa spinosissima x canina = R. x hibernica | IE, VCH39 Co. Antrim, Belfast | Samuel Alexander Stewart | | 12/7/1875 | SLBI |
| Zannichellia palustris | IE, VCH39 Co. Antrim, Belfast | Samuel Alexander Stewart | Botanical Exchange Club of The British Isles Samuel Alexander Stewart | 12/8/1878 | ABS |
+ | Equisetum hyemale x variegatum = E. x trachyodon | IE, VCH39 Co. Antrim, Belfast,Colin Glen | Samuel Alexander Stewart | Botanical Exchange Club | 20/5/1871 | MANCH |
+ | Equisetum hyemale x variegatum = E. x trachyodon | IE, VCH39 Co. Antrim, Belfast,Colin Glen | Samuel Alexander Stewart | Richmond Museum Charles Bailey James Ward | 7/6/1865 | MANCH |
+ | Equisetum hyemale x variegatum = E. x trachyodon | IE, VCH39 Co. Antrim, Belfast,Colin Glen | Samuel Alexander Stewart | Botanical Exchange Club of The British Isles Charles Bailey | 29/7/1893 | MANCH |
| Equisetum hyemale x variegatum = E. x trachyodon | IE, VCH39 Co. Antrim, Belfast,Colin Glen | Samuel Alexander Stewart | Harold Stuart Thompson | 22/6/1879 | BIRM |
+ | Potamogeton praelongus | IE, VCH39 Co. Antrim, Belfast,Lagan Canal | Samuel Alexander Stewart | Charles Bailey James Ward | 2/7/1866 | MANCH |
+ | Potamogeton praelongus | IE, VCH39 Co. Antrim, Belfast,Lagan Canal | Samuel Alexander Stewart | Alfred Fryer Charles Bailey | 23/6/1873 | MANCH |
+ | Stratiotes aloides | IE, VCH39 Co. Antrim, Belfast,Springfield | Samuel Alexander Stewart | Richmond Museum Charles Bailey James Ward | 3/7/1865 | MANCH |
| Carex distans | IE, VCH39 Co. Antrim, Black Head | Samuel Alexander Stewart | | 29/6/1872 | BON |
| Potamogeton perfoliatus | IE, VCH39 Co. Antrim, Bushmills | Samuel Alexander Stewart | Richmond Museum Charles Bailey | 7/1866 | MANCH |
| Mentha aquatica x spicata = M. x piperita | IE, VCH39 Co. Antrim, Carnmoney | Samuel Alexander Stewart | Science & Art Museum Dublin | 14/9/1872 | DBN |
| Mentha aquatica x spicata = M. x piperita | IE, VCH39 Co. Antrim, Carnmoney | Samuel Alexander Stewart | Science & Art Museum Dublin | 12/8/1893 | DBN |
| Alchemilla filicaulis | IE, VCH39 Co. Antrim, Cave Hill | Samuel Alexander Stewart | William Hunt Painter | 5/7/1886 | ABS |
| Pilosella lactucella | IE, VCH39 Co. Antrim, Cave Hill | Samuel Alexander Stewart | | 5/7/1902 | ABS |
| Hieracium orcadense | IE, VCH39 Co. Antrim, Cave Hill, Belfast | Samuel Alexander Stewart | | 21/6/1896 | ABS |
| Orobanche alba | IE, VCH39 Co. Antrim, Cave Hill, Belfast | Samuel Alexander Stewart | Augustin Ley | 8/7/1871 | BIRM |
| Equisetum hyemale x variegatum = E. x trachyodon | IE, VCH39 Co. Antrim, Colin Glen | Samuel Alexander Stewart | Augustin Ley | 1/7/1872 | BIRM |
| Equisetum hyemale x variegatum = E. x trachyodon | IE, VCH39 Co. Antrim, Colin Glen | Samuel Alexander Stewart | Botanical Exchange Club of The British Isles Augustin Ley | 29/7/1893 | BIRM |
| Equisetum hyemale x variegatum = E. x trachyodon | IE, VCH39 Co. Antrim, Colin Glen | Samuel Alexander Stewart | | 1/7/1872 | BON |
+ | Equisetum hyemale x variegatum = E. x trachyodon | IE, VCH39 Co. Antrim, Colin Glen | Samuel Alexander Stewart | | 22/6/1879 | BIRM |
| Pilosella peleteriana | IE, VCH39 Co. Antrim, Core Hill, Belfast Cultivated | Coslett Herbert Waddell | Botanical Exchange Club of The British Isles Coslett Herbert Waddell Edward Francis Linton Samuel Alexander Stewart | 8/1900 | ABS |
| Hieracium latobrigorum | IE, VCH39 Co. Antrim, Cranfield | Samuel Alexander Stewart | | 27/7/1890 | SLBI |
| Hieracium latobrigorum | IE, VCH39 Co. Antrim, Cranfield | Samuel Alexander Stewart | | 27/7/1899 | ABS |
| Carex remota | IE, VCH39 Co. Antrim, Cushendall | Samuel Alexander Stewart | | 28/6/1866 | BM |
| Carex dioica | IE, VCH39 Co. Antrim, Divis Hill | Samuel Alexander Stewart | | 12/5/1866 | BM |
| Scrophularia auriculata | IE, VCH39 Co. Antrim, Four Mile Burn | Samuel Alexander Stewart | Alexander Somerville | 22/7/1883 | E |
| Carex spicata | IE, VCH39 Co. Antrim, Greencastle | Samuel Alexander Stewart | Edward Francis Linton | 19/6/1873 | BM |
| Salix viminalis x caprea = S. x smithiana | IE, VCH39 Co. Antrim, Kilroot | Samuel Alexander Stewart | George Stephen West | 5/1868 | BIRM |
| Hieracium basalticola | IE, VCH39 Co. Antrim, Knockagh | Samuel Alexander Stewart | Botanical Exchange Club of The British Isles | | ABS |
| Potamogeton alpinus | IE, VCH39 Co. Antrim, Lough Mourne | Samuel Alexander Stewart | Alfred Fryer Charles Bailey | | MANCH |
| Potamogeton perfoliatus | IE, VCH39 Co. Antrim, Lough Mourne | Samuel Alexander Stewart | Alfred Fryer Charles Bailey | 19/7/1880 | MANCH |
+ | Calamagrostis stricta | IE, VCH39 Co. Antrim, Lough Neagh | Samuel Alexander Stewart | Botanical Exchange Club Charles Bailey | 30/6/1877 | MANCH |
+ | Calamagrostis stricta | IE, VCH39 Co. Antrim, Lough Neagh | Samuel Alexander Stewart | Botanical Exchange Club Charles Bailey | 30/6/1877 | MANCH |