Amorphophallus, Blume ex Decne.

Serebryanyi, M., Trinh, T. & Hetterscheid, W., 2023, New tuberous Araceae from Binh Thuan Province (South Vietnam), Blumea 68 (1), pp. 39-48 : 43

AMORPHOPHALLUS Blume ex Decne.

The genus Amorphophallus ( Araceae - Aroideae -Thomsonieae) presently contains 200+ species distributed in tropical and subtropical regions of Africa,Asia and northern Australia ( Naive et al. 2022). Recently several species have been described from Vietnam ( Galloway et al. 2019a), Laos ( Galloway 2015, Galloway et al. 2019c), Thailand ( Galloway et al. 2019b), In- donesia ( Yuzammi & Hetterscheid 2020) and the Philippines ( Bustamante et al. 2020, Hetterscheid et al. 2020, Tamayo et al. 2021).

The genus comprises small to giant, seasonal geophytic herbs; underground part usually a (sub)globose or vertically elongate tuber, more rarely a rhizome; leaf usually solitary, more rarely several, rising from the tuber, with a decompound, horizontal lamina; leaflets few to numerous, variable; inflorescence mostly solitary, rarely accompanied by leaves; peduncle short or elongate; spathe folded around the spadix, with or without a con- striction between base and limb, orbicular to narrowly elongate, variously coloured inside and outside; spadix with lower pistillate zone, contiguous or not with an upper staminal zone and above that a sterile appendix (rarely missing); staminodes (when present) between both fertile zones, or within one or both of them; appendix very variable, from subglobose to elongate, erect, horizontal or rarely pendulous; infructescence consisting of sessile berries, these globose or elliptical, red, blue, white, yellow, green or orange at maturity.

With this newly described species included, 37 species of the genus are recorded for the Vietnamese flora, which makes Amorphophallus an irrefutable leader in genus size within the Araceae (31 species were recorded by Nguyen in 2017). Due to active field work of botanists and enthusiasts, knowledge of geo- graphic distribution, ecology and species’ variation is constantly improving. The current number of species will definitely increase due to new findings, including undescribed species. Important to mention, two inter-species spontaneous hybrids are newly recorded for Vietnam, all from the former genus Pseudodracontium , namely Amorphophallus pseudoharmandii (Engl.) Hett. & Claudel × A. fallax , A. pseudoharmandii × A. macrophyllus (Gagnep. ex Serebryanyi) Hett. & Claudel.