| Campanulaceae | |
Lobelia siphilitica fo. alba
| Voss | Vilm. Blumengärtn. ed. 3 1: 576 | 1894 |
| Campanulaceae | |
Lobelia siphilitica var. alba
| G. Don & Baxter | Hort. Brit. ed. 3: 646 | 1839 |
| Campanulaceae | |
Lobelia siphilitica fo. albiflora
| Britton | Bull. Torrey Bot. Club 17(5): 125 | 1890 |
| Campanulaceae | |
Lobelia siphilitica var. bollii
| (E. Wimm.) E. Wimm. | Pflanzenr. 107[IV,276b]: 423 | 1953 |
| Campanulaceae | |
Lobelia siphilitica var. candida
| Alph. Wood | Class-book Bot. 476 | 1881 |
| Campanulaceae | |
Lobelia siphilitica var. densiflora
| (Rennie) E. Wimm. | Ann. Naturhist. Mus. Wien 56: 340 | 1948 |
| Campanulaceae | |
Lobelia siphilitica var. grandis
| E. Wimm. | Pflanzenr. IV, 276b: 422 | 1953 |
| Campanulaceae | |
Lobelia siphilitica fo. hybrida
| (Hook.) Voss | Vilm. Blumengärtn. ed. 3 1: 576 | 1894 |
| Campanulaceae | |
Lobelia siphilitica var. hybrida
| Hook. | Bot. Mag. 64: t. 3604 | 1837 |
| Campanulaceae | |
Lobelia siphilitica fo. laevicalyx
| Fernald | Rhodora 45(539): 476–477 | 1943 |
| Campanulaceae | |
Lobelia siphilitica fo. ludoviciana
| Voss | Vilm. Blumengärtn. ed. 3 1: 576 | 1894 |
| Campanulaceae | |
Lobelia siphilitica var. ludoviciana
| A. DC. | Prodr. 7(2): 377 | 1839 |
| Campanulaceae | |
Lobelia siphilitica var. maculata
| A. DC. | Prodr. 7: 377 | 1839 |
| Campanulaceae | |
Lobelia siphilitica var. milleri
| (Paxton) Steud. | Nomencl. Bot. ed. 2, 2: 63 | 1841 |
| Campanulaceae | |
Lobelia siphilitica var. minor
| Hook. | Compan. Bot. Mag. 1: 100 | 1835 |
| Campanulaceae | |
Lobelia siphilitica fo. purpurea
| E.J. Palmer & Steyerm. | Brittonia 10(3): 118 | 1958 |
| Campanulaceae | |
Lobelia siphilitica fo. purpurea
| Voss | Vilm. Blumengärtn. ed. 3 1: 576 | 1894 |
| Campanulaceae | |
Lobelia siphilitica var. rosea
| N. Coleman | Kent Sci. Inst. Misc. Publ. 2: 24 | 1874 |
| Campanulaceae | |
Lobelia siphilitica fo. siphilitica
| | | |
| Campanulaceae | |
Lobelia siphilitica var. siphilitica
| | | |
| Campanulaceae | |
Lobelia siphilitica var. speciosa
| (Sweet) Steud. | Nomencl. Bot. ed. 2, 2: 63 | 1841 |