| 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 |
| Utricularia minor | IE, VCH16 West Galway, Roundstone | Samuel Alexander Stewart | William Hadden Beeby | | SLBI |
+ | 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 |
+ | Stratiotes aloides | IE, VCH39 Co. Antrim, Belfast,Springfield | Samuel Alexander Stewart | Richmond Museum Charles Bailey James Ward | 3/7/1865 | MANCH |
| Lobelia dortmanna | IE, VCH38 Co. Down, Mourne Mountains | Samuel Alexander Stewart | Richmond Museum Charles Bailey James Ward | 7/9/1865 | MANCH |
| Carex dioica | IE, VCH39 Co. Antrim, Divis Hill | Samuel Alexander Stewart | | 12/5/1866 | BM |
| Carex remota | IE, VCH39 Co. Antrim, Cushendall | Samuel Alexander Stewart | | 28/6/1866 | BM |
| Potamogeton perfoliatus | IE, VCH39 Co. Antrim, Bushmills | Samuel Alexander Stewart | Richmond Museum Charles Bailey | 7/1866 | MANCH |
| Potamogeton alpinus | IE, VCH39 Co. Antrim, Belfast | Samuel Alexander Stewart | Richmond Museum Charles Bailey James Ward | 2/7/1866 | MANCH |
+ | Potamogeton praelongus | IE, VCH39 Co. Antrim, Belfast,Lagan Canal | Samuel Alexander Stewart | Charles Bailey James Ward | 2/7/1866 | MANCH |
+ | Calamagrostis stricta | IE, VCH39 Co. Antrim, Toomebridge,Lough Beg | | Charles Bailey James Ward Samuel Alexander Stewart | 8/7/1866 | MANCH |
+ | Galeopsis versicolor | IE, VCH38 Co. Down, Rathmullan | Samuel Alexander Stewart | Charles Bailey James Ward | 26/7/1866 | MANCH |
+ | Eriocaulon aquaticum | IE, VCH16 West Galway, Connemara,Roundstone | Samuel Alexander Stewart | Charles Bailey | 29/7/1867 | MANCH |
| Eriocaulon aquaticum | IE, VCH16 West Galway, Roundstone | Samuel Alexander Stewart | | 29/7/1867 | BON |
| Salix viminalis x caprea = S. x smithiana | IE, VCH39 Co. Antrim, Kilroot | Samuel Alexander Stewart | George Stephen West | 5/1868 | BIRM |
+ | Calamagrostis stricta | IE, VCH39 Co. Antrim, Toomebridge,Lough Beg | Samuel Alexander Stewart | Charles Bailey | 8/7/1868 | MANCH |
| Spergularia rupicola | IE, VCH38,VCH39, Belfast | Samuel Alexander Stewart | George Stephen West | 8/1869 | BIRM |
| Atriplex laciniata | IE, VCH38 Co. Down, Groomport | Samuel Alexander Stewart | Augustin Ley | 10/9/1870 | BIRM |
+ | Equisetum hyemale x variegatum = E. x trachyodon | IE, VCH39 Co. Antrim, Belfast,Colin Glen | Samuel Alexander Stewart | Botanical Exchange Club | 20/5/1871 | MANCH |
| Rosa spinosissima x canina = R. x hibernica | IE, VCH38 Co. Down, Holywood | Samuel Alexander Stewart | Frederick Arnold Lees | 6/1871 | SLBI |
| Orobanche alba | IE, VCH39 Co. Antrim, Cave Hill, Belfast | Samuel Alexander Stewart | Augustin Ley | 8/7/1871 | BIRM |
| Lavatera arborea | IE, VCH38 Co. Down, Groomsport | Samuel Alexander Stewart | William Hadden Beeby | 15/7/1871 | SLBI |
| Melampyrum sylvaticum | IE, VCH38,VCH39, Belfast | Samuel Alexander Stewart | Augustin Ley | 12/6/1872 | BIRM |
| Carex elata | IE, VCH39 Co. Antrim, Portmore | Samuel Alexander Stewart | Augustin Ley | 20/6/1872 | BIRM |
| Carex distans | IE, VCH39 Co. Antrim, Black Head | Samuel Alexander Stewart | | 29/6/1872 | BON |
| 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 | | 1/7/1872 | BON |
| Mentha aquatica x spicata = M. x piperita | IE, VCH39 Co. Antrim, Carnmoney | Samuel Alexander Stewart | Science & Art Museum Dublin | 14/9/1872 | DBN |
| Carex spicata | IE, VCH39 Co. Antrim, Greencastle | Samuel Alexander Stewart | Edward Francis Linton | 19/6/1873 | BM |
+ | Potamogeton praelongus | IE, VCH39 Co. Antrim, Belfast,Lagan Canal | Samuel Alexander Stewart | Alfred Fryer Charles Bailey | 23/6/1873 | MANCH |
| Rosa spinosissima x canina = R. x hibernica | IE, VCH39 Co. Antrim, Belfast | Samuel Alexander Stewart | | 12/7/1875 | SLBI |
| Arctostaphylos uva-ursi | IE, VCH9 Co. Clare, Black Head | Samuel Alexander Stewart | Robert Large Baker | 5/1876 | BIRM |
+ | Hymenophyllum wilsonii | IE, VCH16 West Galway, Twelve Pins,Bengower | Samuel Alexander Stewart | Charles Bailey | 10/5/1876 | MANCH |
| Saxifraga umbrosa | IE, VCH16 West Galway, Ben Lettery | Samuel Alexander Stewart | William Hadden Beeby Arthur Bennett | 10/5/1876 | SLBI |
| Saxifraga umbrosa var. punctata | IE, VCH16 West Galway, Connemara | Samuel Alexander Stewart | Augustin Ley | 10/5/1876 | BIRM |
| Saxifraga umbrosa x spathularis = S. x urbium | IE, VCH16 West Galway, Connemara | Samuel Alexander Stewart | Charles Bailey | 10/5/1876 | MANCH |
| Dryas octopetala | IE, VCH9 Co. Clare, Black Head | Samuel Alexander Stewart | | 12/5/1876 | SLBI |
| Gentiana verna | IE, VCH9 Co. Clare, blackhead | Samuel Alexander Stewart | William Hadden Beeby | 12/5/1876 | SLBI |
| Arctostaphylos uva-ursi | IE, VCH9 Co. Clare, Black Head | Samuel Alexander Stewart | Augustin Ley | 13/5/1876 | BIRM |