Lobelia tortuosa A. Heller , Minnesota Bot. Stud. 1: 912. 1897.
Type information:
Lectotype [MIN]. A.A. Heller 2443. 25 June 1895. Kaua`i: Hanapepe and Wahiawa watershed, [perpendicular cliffs along the Hanapepe River].
Lectotypified in W. L. Wagner and R. K. Shannon. Brittonia 51: 429. 1999. Isolectotype(s) [A, BISH, F [2], GH [2], MASS, MO, NY [2,mfc!, fragment BISH!, photo BISH!], P [2], US!].

Note: Nom. illegit., non Kuntze (1891). Collection 2443, pro parte. Additional syntypes: 24-26 June 1895, Heller 2443 (F [2], NY! [mfc, fragment BISH!, photo BISH!], US!) and 2-8 July (MO!, US!). Heller did not cite a date and thus all of the collections distributed under this number are syntypes.

=Lobelia niihauensis
Note: Nom. illegit., non Kuntze (1891). Collection 2443, pro parte. Additional syntypes: 24-26 June 1895, Heller 2443 (F [2], NY! [mfc, fragment BISH!, photo BISH!], US!) and 2-8 July (MO!, US!). Heller did not cite a date and thus all of the collections distributed under this number are syntypes.

*Verification: Wagner, W.L. & R.K. Shannon. 1999. Brittonia 51:422-438.

Lobelia tortuosa A. Heller f. glabrata Skottsb., Acta Horti Gothob. 2: 263. 1926.
Type information:
Holotype [GB]. C. Skottsberg 1057. 31 October 1922. Kaua`i: Okolele ditch trail, on canyon wall.
=Lobelia niihauensis

*Verification: T.G. Lammers.

Lobelia tortuosa A. Heller var. haupuensis H. St. John, Phytologia 62: 435. 1987.
Type information:
Holotype [BISH]. W.C. Gagné and S.L. Montgomery 570. 30 August 1970. Kaua`i: Ha`upu, Hoary Head Mts., wet, windy, steep, N facing slope on exposed rock face.500m.
=Lobelia niihauensis

*Verification: T.G. Lammers.

Lobelia tortuosa A. Heller var. intermedia H. St. John, Occas. Pap. Bernice P. Bishop Mus. 15(2): 24. 1939.
Type information:
Holotype [BISH]. C.N. Forbes and C.H. Dole 70.K. 19 July 1909. Kaua`i: Kalalau Trail. Isotype(s) [BISH! [2], US! [2], W! [3]].
=Lobelia niihauensis

*Verification: T.G. Lammers.