Volume 11 > Part 2 > Year 2012 > Page 180 > Araceae > Amorphophallus

52. Amorphophallus tenuistylis Hett.

Blumea 39(1–2): 279. 1994.

Accepted Name : This is currently accepted.

Description : Tuber elongate, napiform, 11–16 by 2–5 cm, unbranched. Leaf solitary; petiole 70–80 cm by 7–9 mm, turgid, smooth, largely pale green with narrowly elongate-elliptic, pale to dark green spots, blackish green at the base, or largely dirty pale grey with elongate-elliptic, dark olive-green spots, often confluent, and some similar small dots near the base, or almost entirely dark olive-green with numerous small, greyish punctate spots; leaf blade 20–100 cm diam., rachises narrowly winged throughout; leaflets elliptic, elongate-elliptic or lanceolate, 5–12 by 2–3.5 cm, short acuminate. Inflorescence: peduncle 30–100 cm by 7–20 mm, greyish to pale grey with elongate, often confluent, olive-green or dark brown spots and scattered small whitish dots; spathe erect, elliptic-lanceolate to elongate-triangular, 17–40 by 7–20 cm, base convolute and separated from the limb by a shallow constriction, apex acute, margin strongly sinuous, sometimes spirally twisting around the midrib, exterior appearance as petiole but limb flushed maroon, interior base pale to dark maroon, limb dark maroon, or dirty green with purple-brown flushes, darker near the margin, or dirty pale grey with orbicular, dark green spots around the midrib and the remainder dark purple, base within densely clothed with short and long, more or less fleshy, elongate, hair-like warts, sometimes with a few irregular branches; spadix sessile or stipitate, stipe to ca 7 mm, shorter to distinctly longer than spathe, 7–50 cm long; pistillate flower zone cylindrical, flowers slightly or distinctly distant, 1–6.5 by 1–2 cm (incl. styles), with or without a very short naked interstice at the apex; ovaries depressed, oval in outline, 2–4 by 1–2 mm, more or less bright pale green; style slender, 3–4 by 0.6–0.8 mm, dark brown or pale purple; stigma obconical, 1.5–2 by ca 1 mm, entire or shallowly, or distinctly 2–(3–)lobed, lobes hemispherical or conical, surface echinulate, off-white or pale yellow; sterile interstice absent or present, ca 8 mm, staminodes congested; staminate flower zone cylindrical or slightly conical, 3.5–11 by 1–1.5 cm, base truncate, flowers congested; staminate flowers (2–)4–6-androus, slightly enlarged in the lowermost part of the staminate flower zone, or staminodial; stamens 2–3 mm long; off-white or purplish brown; anthers 1–1.3 by 1–1.5 mm, dark brown to blackish brown; appendix elongate, thin, acute, in smaller inflorescences myosuroid, 2.5–32 cm by 4–10 mm, lower part sometimes verrucate, otherwise smooth, brownish grey. Fruit not seen.

Thailand : SOUTH-WESTERN: Uthai Thani (type: Maxwell 76-250, holotype -L, isotypes -AAU BK CMU), Kanchanaburi; SOUTH-EASTERN: Sa Kaeo.

Distribution : Cambodia.

Ecology : Open mixed bamboo and deciduous forests, on limestone; ca 200 m alt.

Vernacular : Buk (บุก)(Southwestern).

Notes: A very distinct species by the unique combination of the elongate tuber and the long styles carried at right angles to the spadix-axis. The warts in the spathe-base are reminiscent of those in Amorphophallus longituberosus and A. albispathus, though they are not as long nor branched in these species. Both are, however, the nearest morphological allies of A. tenuistylis, also taking into account the three-locular ovary and the enlarged lower staminate flowers, common to this species-group.