Volume 11 > Part 2 > Year 2012 > Page 160 > Araceae > Amorphophallus

29. Amorphophallus lunatus Hett. & Sizemore

Aroideana 29: 64. 2006. Plate XXVI: C–D.

Accepted Name : This is currently accepted.

Description : Tuber short or long elongate, rarely branching, to 20 by 5 cm. Leaf solitary; petiole terete, 25–70 cm by 7–19 mm, uniformly pale reddish brown or with narrow, whitish pinkish longitudinal stripes or linear spots; leaf blade 17–60 cm wide, main segments with few, relatively large leaflets, winged to the base; leaflets elliptic-oblong, 6–18 by 2.8–8.5 cm, acute-acuminate, adaxially rich dark green, margin narrowly lined purplish red, abaxially pale green, margin as adaxially. Inflorescence solitary; peduncle 20–40 cm by 5–10 mm, appearance as petiole; spathe ovate to broadly ovate, slightly concave, erect, 6–11.5 by 4–13 cm, greenish white all over, margins involute, apex acute, slightly hooded, base within densely clothed with short, fleshy, complexly branched verrucae; spadix sessile, longer than spathe, 11.5–30 cm long; pistillate flower zone cylindrical, 5–11 by 7–11 mm, flowers more or less congested; ovaries strongly depressed, 1 by 2.5–3 mm, pale green, bilocular; style 0.4 by 1.5 mm, white; stigma disciform, 0.3 by 2 mm, subentire to shallowly 4–5-lobed, grooves between lobes radiating from the centre, central depression slightly elongate, margin sometimes slightly notched and lobed-sinuous, surface minutely rugulose, white; sterile interstice present or absent, staminodes congested; staminodes as staminate flowers but slightly shorter and without thecae; staminate flower zone cylindrical to cylindrical-conical, 3–5 cm by 6–13 mm at the base, 5–12 mm at the apex, base slightly constricted, flowers congested; staminate flowers 2–5-androus; stamens polygonal in cross-section, whitish; appendix narrowly elongate conical, 8–24 cm by 7–20 mm, tapering from base to apex, laterally flattened, base slightly attenuate, apex narrowly obtuse or acute, surface irregularly rugulose, pale yellowish green. Infructescence cylindrical, 3–6 by 3 cm; fruits ovoid-lageniform, 10–15 by 6–10 mm, the swollen basal region of the style prominent, smooth, ripening white.

Thailand : NORTHERN: Nakhon Sawan; SOUTH-WESTERN: Kanchanaburi (type: Sizemore cult. sub. Hetterscheid H.AM. 1358-T, holotype -WAG).

Distribution : Endemic.

Ecology : Secondary scrub.

Notes: The inflorescence of Amorphophallus lunatus resembles that of A. saururus but the style is much shorter. From A. sizemoreae, A. lunatus differs by its much smaller inflorescence, smaller leaf and bilocular (vs unilocular) ovary. The typical shape of the pores in the lower staminate flowers is shared with A. operculatus.