Amorphophallus subgen. Scutandrium, Blume ex Decaisne, 1834

Scholten, Justin, Livingston, David & Sizemore, Mary, 2024, A new Amorphophallus (Araceae) species from Thailand and an updated key to the Longituberosus and Saraburiensis subclades, Phytotaxa 633 (2), pp. 101-107 : 105-106

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