AMORPHOPHALLUS EXCENTRICUS
PROTOLOGUE: Amorphophallus excentricus Hett., published in Blumea 39: 255 (1994).
Ab Amorphophallus asterostigmato Bogner & Hett. in appendice multo solida, stigmate tenuissimo non stellatolobato differt.
Typus: Hetterscheid H.AM. 154-T (L holo; spirit coll.), 19-viii-1992, cult. Hort. Bot. Leiden ex Thailand, Phuket Island, National Park, near Ton Sai Falls, c. 250 m alt. (orig. coll. M. Koenen, 1986).
SYNONYMS:
OTHER NAMES: Thai: Buk (บุก)(Peninsular).
DISTRIBUTION: S. Pen. Thailand to Pen. Malaysia (Pulau Langkawi): Peninsular Malaysia, Thailand.
DISTRIBUTION NOTE: Ban Kawp Kep, Surat (Surat Thani), and Kaw Titi, Krabi, Peninsular Thailand.
SPECIES DESCRIPTION:
Tuber subglobose, yellowish brown, up to 10 cm in diam., developing globose offsets, attached to the main tuber by a short rhizomatous part. Leaf solitary; petiole up to c. 130 cm long, c. 2.5 cm in diam. (base), smooth, ground colour a very pale, dirty greenish grey or creamish, to the base pale reddish violet, covered with more or less elliptic, blackish green or dirty brownish green spots, these with a sharply defined acroscopic margin and a diffuse basiscopic margin, in between several scattered, tiny white dots; lamina up to c. 160 cm in diam., distal part of the rachises winged, wings narrowly wedge-shaped; leaflets elliptic-lanceolate, acuminate, 12–24 cm long, 4–7 cm in diam., upper surface dull green, lower surface paler green.
INFLORESCENCE:
Inflorescence solitary, long peduncled; peduncle 45–62 cm long, 1.2–1.3 cm in diam. (base), as petiole or in all parts with an extra brownish hue; spathe erect, cymbiform, ovate-triangular, acute, mucronate, 18–24 cm long, 10–11.5 cm in diam., basal part convolute, margin slightly recurved, base outside whitish green to green, near the base with a few diffuse, dark green spots and numerous small, white dots, inside pale whitish green, limb outside green, inside whitish, to the margin and near the top suffused with pale pink, base within with numerous, small, rounded or longitudinally elongate warts.
Spadix sessile, slightly longer or shorter than spathe, 18–24 cm long; female part cylindric or slightly fusiform, 2–3 cm long, 1–1.4 mm in diam., flowers all congested or less so near the base; male part cylindric or slightly obconic, 5–8 cm long, 1.2–1.3 cm in diam., flowers congested; appendix elongate fusiform, dorsoventrally flattened, top acute or slightly rounded, base constricted, 9–12 cm long, 2.2–2.6 cm in diam., surface irregularly, shallowly grooved and minutely rugulose, white.
Ovaries depressed, base acute, slightly angulate in cross section, 2–3 mm in diam., 1–1.5 mm high, pale green, unilocular; style short and thick, 0.5–1 mm long, 1–2 mm in diam., pale green, very excentrically inserted near the acroscopic margin of the ovary; stigma thin, 1.5–2.5 mm in diam., 0.5–1 mm high, irregularly angulate in cross section, surface irregularly sulcate with a central, shallow, star-shaped depression or more or less 3- or 4-lobed, verruculate, yellowish to brownish, margin undulate. Male flowers consisting of 3–5 stamens; stamens 2 mm long, 1.5–2 mm in diam.; anthers truncate, with two apical to subapical, elongate pores, off-white. Pollen striate.
ECOLOGY:
In evergreen forests, in scrub, recorded at approximately 50 m elevation.
DISTRIBUTION MAPS:
ETYMOLOGY:
From Latinized Greek excentricus, “off-center” or “eccentric,” referring to the distinctly off-center insertion of the style near the margin of the ovary.
NOTES:
1. Amorphophallus excentricus is morphologically similar to Amorphophallus asterostigmatus Bogner & Hett. but differs among others by its much heavier appendix, the lack of basal staminodes on the appendix and a much flatter stigma.
2. Amorphophallus excentricus is morphologically very similar to Amorphophallus carneus
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus excentricus Hett.
2. Blumea 39: 255 (1994) — protologue.
3. Alan Galloway — Amorphophallus excentricus, alangallowaybotanicals.com.
Additional photos by Ian Wintle