A new Amorphophallus (Araceae) species from Thailand and an updated key to the Longituberosus and Saraburiensis subclades Author Scholten, Justin Department of Plant Biology, 516 Mann Library, Cornell University, Ithaca, New York 14853, United States of America. Author Livingston, David 3318 Ellington Ct., Ft. Myers, Florida 33916, United States of America. Author Sizemore, Mary 751 Deerfoot Rd., Deland, Florida 32720, United States of America. text Phytotaxa 2024 2024-01-05 633 2 101 107 https://phytotaxa.mapress.com/pt/article/download/phytotaxa.633.2.1/51414 journal article 10.11646/phytotaxa.633.2.1 1179-3163 10462290 Key to the species of the Longituberosus and Saraburiensis subclades of Amorphophallus subgen. Scutandrium Species treated: A. albispathus ( Thailand ) A. bantae ( Thailand ) A. coudercii (C. Vietnam , Cambodia ) A. longituberosus (NW Malaysia , Thailand ) A. saraburiensis (C. Thailand ) A. scutatus (C. Thailand ) A. tenuispadix (C. Thailand ) A. tenuistylis (C. Thailand ) 1. Spadix distinctly longer than spathe; synandrodes present or not.....................................................................................................2. – Spadix as long or shorter than spathe; synandrodes absent...............................................................................................................4. 2. Spathe base interior covered in fleshy, hair-like projections; synandrodes often absent ................................................ A. tenuistylis – Spathe base interior verrucose; synandrodes always present ............................................................................................................3. 3. Styles short, 1–2 mm long......................................................................................................................................... A. saraburiensis – Styles 3–4 mm long............................................................................................................................................................ A. scutatus 4. Appendix absent ............................................................................................................................................................... A. coudercii – Appendix present...............................................................................................................................................................................5. 5. Appendix reddish-brown, less broad than staminate zone ................................................................................................... A. bantae – Appendix white or beige, at least 1.25× as broad as staminate zone ................................................................................................6. 6. Staminate pores located at the periphery of thecae; spathe exterior often with vertical stripes............................... A. longituberosus – Staminate pores located near the center of thecae; spathe exterior always without stripes ..............................................................7. 7. Ovaries 3–4-locular; peduncle and spathe without mottles........................................................................................... A. albispathus – Ovaries unilocular; peduncle and/or spathe often mottled ............................................................................................ A. tenuispadix