AMORPHOPHALLUS SCUTATUS

PROTOLOGUE: Amorphophallus scutatus Hett. & T.C.Chapm., published in Blumea 46: 270 (2001).

Amorphophallus scutatus Hett. & T.C. Chapm., spec. nov. Amorphophallo saraburiensi similis, stylis duplo ad triplo longioribus spadicis axe valde parallelis differt. - Typus: Hetterscheid H.AM.589-T (holo L, spirit coll.), Thailand, Petchabun prov., exact loc. unknown (coll. from a plant cultivated in the Leiden Botanical Garden; orig. coll. T.C. Chapman s.n.).

DISTRIBUTION: Thailand: Thailand.

DISTRIBUTION NOTE: Thailand: Petchabun and Saraburi Provinces.².

SPECIES DESCRIPTION:

Tuber elongate, white, to 25 cm long and 6 cm across, not branching. Petiole 40-50 cm long and 0.9-1 cm across, smooth and turgid, the background pale green with elongate elliptic grey-green spots, or very pale flesh-coloured to whitish grey with a silvery shimmer and very tiny blackish dots, or creamy white with small olive brown-green dots and largely covered by elongate elliptic, confluent olive green-brown spots. Lamina to 100 cm across, the rachises narrowly winged throughout; leaflets linear, lanceolate, elliptic or elliptic-lanceolate, 5-10 cm long and 0.7-4 cm across, acuminate.²

INFLORESCENCE:

Inflorescence solitary and long-peduncled; peduncle slender, 20-55 cm long and 6-8 mm across, smooth, patterned as the petiole or with the dark spots confluent to almost entirely covering the background. Spathe triangular to lanceolate, 8.5-20 cm long and 5-8 cm across, the limb and base not strongly differentiated, the base convolute, the limb slightly folded lengthwise and sometimes forming a tube during anthesis or slightly reflexing; outside pale grey or grey-green with darker veins, a few or many tiny greenish grey spots and scattered rounded indistinct grey or whitish spots, the margin brownish or dull dark greyish; inside the base purple, the rest grey, green or grey-green flushed upwards with dark greyish brown; the base within verrucate, the warts fleshy, the lower ones elongate and papillate, the upper ones conical or flaky, whitish or pale purple. Spadix shorter or distinctly longer than the spathe, substipitate, 14-26 cm long; female zone cylindric, 1.5-2.5 cm long and 0.8-1 cm across, the flowers congested or slightly distant; a sterile zone between the male and female zones 0.5-1 cm long and 0.7-0.8 cm across, the staminodes congested; male zone cylindric, 2-3.5 cm long and 0.7-0.9 cm across, the flowers congested; appendix thin elongate conical, 9.5-20 cm long and 0.8-1 cm across at the base, the top obtuse, the base shallowly ridged and the rest rugulose, pale olive green, pale whitish grey or pale brown, giving off a heavy gaseous or pungent cheesy stench. Ovaries depressed, subcircular or circular in cross section, 3 mm across and 1 mm high, bright green, purple near the base of the style, 1-locular; style 3-4 mm long and 1 mm across at the base, purple, strongly parallel to the axis of the spadix; stigma depressed but strongly folded, laterally displaced or apical, about 1.5 mm across and 0.6 mm high, notched at the raised acroscopic side or at the sides where the elongate style branches appear, off-white, the surface papillate-echinulate. Staminodes flat, rhombic, oval or egg-shaped, 3-5 mm long and 3 mm across, the margins slightly raised or not, the surface very shallowly rugulose, pale green, pale whitish grey or pale brown. Male flowers of 2 or 3 stamens; stamens shallowly hemispheric, broad, spindle-shaped or irregular, about 2 by 1 mm in cross section and about 1.5 mm high; filaments entirely fused and broadened beyond the base of the anthers, about 0.5 mm high, pale green to off-white; anthers about 1 mm high, subtruncate, dark or pale purple, the connective flat or slightly raised; pores slit-like before anthesis, often laterally fused into one long curved slit. Pollen areolate, spheroidal, 51 µm long.²

ETYMOLOGY:

From Latin scutum, “shield”: the staminodes at the base of the male zone are flat and rhombic to egg-shaped, like small shields. Sterile flowers of that shape are unusual enough in the genus to name a species by.²

NOTES:

1. Amorphophallus scutatus is closely similar to Amorphophallus saraburensis, from which it differs in styles twice as long that lie strongly parallel to the axis of the spadix.²

2. The leaflets are remarkably variable. One cultivated clone has elliptic leaflets and another has linear ones - a range of variation rarely found within a single species of Amorphophallus.²

3. The scent is described as heavy and gaseous, or pungently cheesy.²

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus scutatus Hett. & T.C.Chapm.

2. Blumea 46: 270 (2001) — protologue.

3. Alan Galloway — Amorphophallus scutatus, alangallowaybotanicals.com.