Volume 11 > Part 2 > Year 2012 > Page 177 > Araceae > Amorphophallus

48. Amorphophallus sumawongii (Bogner) Bogner & Mayo

Aroideana 8(1): 19 1985.— Thomsonia sumawongii Bogner, Plant Syst. Evol. 125: 15. 1976.

Accepted Name : This is currently accepted.

Description : Tuber napiform, irregularly branched, 6–20 by 2–6 cm. Leaf solitary; petiole smooth, 20–40 cm by 6–10 mm, greenish or reddish, to various extent with narrowly elongate, whitish, greenish grey or reddish grey spots; leaf blade 20–80 cm, rachises narrowly winged in the distal half; leaflets elliptic to oblong-elliptic, 7–21 by 3.5–8 cm, acuminate, adaxially dark green, abaxially brighter. Inflorescence solitary, long pedunculate; peduncle appearance as petiole, 27–60 cm by 4–8 mm; spathe erect, elliptic, base shortly convolute, apex acute, ± hooded, 6–8.5 by ca 3 cm, yellowish, bright green or more or less purplish or reddish with yellowish spots, base within minutely verrucate and with some scattered, larger echinae; spadix shorter than spathe, sessile, 4–8 cm long; pistillate flower zone cylindrical, 5–10 by ca 5 mm, flowers congested; ovaries subglobose or obovate, slightly depressed, ± diamond-shaped in cross-section, 1.7–2 mm, bright green; stigma sessile, small, disciform, circular in cross-section, ca 0.5 by 0.1–0.2 mm high, yellow, surface verrucate and often with some shallow depressions; staminate flower zone cylindrical, 1.5–2.5 cm by 6–9 mm, flower lax, the lower ones more distant than the upper; staminate flowers 2–3-androus, the lower ones larger than the upper; stamens 2–3 mm long, yellow; appendix conical, apex obtuse or subacute, 1.8–4.5 by ca 1 cm, entirely covered with staminodes, white; staminodes of appendix elongate, truncate, free or partly to entirely connate, ca 1.5–2.5 by 0.5–2.5 mm, rounded or irregular in cross-section. Infructescence cylindrical, ca 4 by 2 cm; fruits globose, ca 5 by 5 mm, surface wrinkled and locally costate, pale green when ripe.

Thailand : SOUTH-EASTERN: Sa Kaeo (Wathana Nakhon – type: Bogner 372, holotype -M, isotypes -K US).

Distribution : Endemic.

Ecology : Dry dipterocarp forests; ca 120 m alt.

Vernacular : Buk (บุก)(Southeastern).

Uses: Inflorescences are sold in markets and eaten as a vegetable after being boiled in water, tasting like Asparagus (Bogner, 1976: 18).

Notes: The inflorescence of Amorphophallus sumawongii is similar to that of A. longituberosus but differs markedly in the elongate staminodes on the appendix. It also resembles members of the Pseudodracontium-alliance in Amorphophallus but differs in having bithecal anthers and always flowering before the leaf.