In 1949, Huttleston gave formal descriptions of three subspecies of Arisaema triphyllum. He also described a fourth subspecies in 1981. These four taxa are members of a closely-related group of species now known as the Arisaema triphyllum species complex.

• Huttleston, Donald G. (1949). "The three subspecies of Arisaema triphyllum". Bulletin of the Torrey Botanical Club. 76 (6): 407–413. doi:10.2307/2482333
• Huttleston, Donald G. (1981). "The four subspecies of Arisaema triphyllum". Bulletin of the Torrey Botanical Club. 108 (4): 479–481. doi:10.2307/2484449

Huttleston’s papers are not readily available online. When I finally obtained copies, I discovered that the 1981 paper contained a comprehensive table of characters that is generally useful. That table has been reproduced in the following document:

• The subspecies of Arisaema triphyllum (googledoc)

Some notes and a brief glossary are included as well.