AMORPHOPHALLUS POLYANTHUS

PROTOLOGUE: Amorphophallus polyanthus Hett. & Sizemore, published in Blumea 46: 267 (2001).

Amorphophallus polyanthus Hett. & M. Sizemore, spec. nov. Ab Amorphophalli speciebus omnibus differt in inflorescentiis 1-15 per anni tempore evolutis saepe aliquot simultaneis. Amorphophallo pusillo similis, spathae basi convoluta, stigmate sessili differt. - Typus: Hetterscheid H.AM.873-T (holo L, spirit coll.), Thailand, Loei prov., near Pha Nok Khan (coll. from a cultivated plant in the Leiden Bot. Garden; orig. coll. M. Sizemore).

DISTRIBUTION: NE. Thailand: Thailand.

DISTRIBUTION NOTE: Thailand: Loei Province - near Pha Nok Khan; known only from the type locality.².

SPECIES DESCRIPTION:

Tuber elongate, branched, to c. 10 cm long, 2.5 cm diam., white. Petiole to 15 cm long, to 6 mm diam., smooth, pale green; lamina to 26 cm diam., subpedate, rachises unwinged, anterior segment undivided; leaflets rhombic, 3-10 cm long, 2-5.5 cm diam., upper surface green.²

INFLORESCENCE:

Inflorescences rarely solitary, often appearing several months after the leaves, one terminal from a petiolar sheath and the next ones directly from the rim of the upper part of the tuber, often developing simultaneously, short peduncled; peduncle entirely or largely subterranean, 1-3 cm long, 2-5 mm diam., smooth, white; spathe broadly triangular, 2-4 cm long, 2.5-5 cm diam., base and limb separated by a shallow constriction, base strongly convolute, partly subterranean or entirely exposed, outside greyish, inside smooth, dark purple, limb erect, strongly concave, acute, margin with elongate glandular epidermal cells giving a microfimbriate appearance, outside dirty whitish with many minute greyish flesh-coloured dots, inside dirty whitish with minute greyish purple dots. Spadix sessile, much longer than spathe, 6.5-13 cm long; female zone cylindric, 1-3 mm long, 5-6 mm diam., flowers in 1-3 rows, congested; male zone cylindric, 4-7 mm long, 4-6 mm diam., flowers congested, or partly vertically separated and arranged in oblique near-verticils; appendix elongate, 6-12 cm long, 4-7 mm diam., thin, straight or slightly sigmoid, acute, terete or slightly dorsoventrally compressed, slightly narrowing to the base, dirty pale greyish brownish, surface densely verruculate. Ovaries irregularly 2- or 3-lobed, 1-1.5 mm diam., c. 1 mm high, 2- or 3-locular, white with a few minute pinkish dots; style very short, 0.05-0.2 mm long, c. 0.3 mm diam. at the top, conical, white; stigma depressed, irregularly elongate or triradiate, 0.2-0.3 mm diam., c. 0.1 mm high, dirty brown or white, papillate. Male flowers consisting of 1-3 stamens; stamens 0.5-0.8 mm diam., c. 0.5 mm long; filaments c. 0.2 mm long, connate; anthers c. 0.3 mm long, truncate, orange.²

ECOLOGY:

Found in deep shade near the base of a rocky outcrop²

ETYMOLOGY:

From Greek polys, “many,” and anthos, “flower”: the epithet records the habit the diagnosis leads with - one plant produces from one to fifteen inflorescences in a season, often several of them at once.²

NOTES:

1. Diagnosis: it differs from every other species in the genus in producing 1-15 inflorescences in a season, often several simultaneously. It is similar to Amorphophallus pusillus but differs in the convolute spathe base and the sessile stigma.²

2. Amorphophallus polyanthus is a close relative of Amorphophallus pusillus of Vietnam and Amorphophallus obscurus of Thailand, sharing their diminutive proportions, colour patterns and leaf shape.²

3. The inflorescences arrive in an unusual way: the first comes terminally from a petiolar sheath, and the ones that follow break directly from the rim of the top of the tuber. The peduncle is largely or entirely underground, so the spathe opens at or near soil level.²

4. Wilbert Hetterscheid, co-author of the species, noted that it has a strong tendency to flower immediately after leaf senescence sets in, sometimes while old leaves are still more or less present. For a mature plant he advised not withholding water when the leaves start to turn yellow, then keeping the plant dry after flowering, although now and then he found plants thriving again quite soon after flowering.⁴

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus polyanthus Hett. & Sizemore

2. Blumea 46: 267 (2001) — protologue.

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

4. Aroid-L mailing list, Wilbert Hetterscheid, February 22nd, 2010