AMORPHOPHALLUS TENUISTYLIS

PROTOLOGUE: Amorphophallus tenuistylis Hett., published in Blumea 39: 279 (1994).

Amorphophallus tenuistylis Hett., spec. nov. Ab omnibus speciebus in tubere elongato, stylis longissimis 3-4 mm longis differt. - Typus: Maxwell 76-250 (L holo; iso AAU, BK), Thailand, Utaithani Prov., Bahn Rai District, Huay Kha Kaeng Reserve, near Kow Hin Dang, in open bamboo/deciduous forest, alt. 200 m, 21-iv-1976.

DISTRIBUTION: S. Thailand to Vietnam: Cambodia, Thailand, Vietnam.

DISTRIBUTION NOTE: Thailand: central and west-central Thailand - Uthai Thani Province, in the Huai Kha Khaeng reserve near Khao Hin Daeng, and Kanchanaburi Province, in Erawan National Park.².

SPECIES DESCRIPTION:

Tuber elongate, turnip-shaped, 11-16 cm long and probably longer, the upper part 2-3 cm across as measured on dried material. The leaf has never been seen.²

INFLORESCENCE:

Inflorescence solitary. Peduncle 64-88 cm long and 1-2 cm across at the base, mottled greyish and olive-green. Spathe erect, lanceolate to elliptic-lanceolate, the base convolute and the top acute, 19-40 cm long and 7-20 cm across, outside mottled greyish and olive-green, inside as outside but with the base maroonish and densely clothed with short and long, more or less fleshy, often hair-like warts, sometimes with a few irregular branches. Spadix slightly to distinctly longer than the spathe, sessile, 24-48 cm long; female part cylindric, the flowers slightly distant, 2-6.5 cm long and 1-2 cm across including the styles, with or without a very short naked gap at the top; male part cylindric with a truncate base, the flowers congested, 6-11 cm long and 1-1.5 cm across; appendix elongate and acute, myosuroid in smaller inflorescences and otherwise sturdier, warted in the lower part and otherwise smooth, brownish grey, 16-30 cm long and 0.4-0.8 cm across at the base. Ovaries depressed, oval in outline, 2-3 mm across and 1.5-2 mm high, 3-locular with one basal ovule in each chamber; style slender, 3-4 mm long and 0.6-0.8 mm across; stigma hemispheric or slightly depressed, 1.5-2 mm across and about 1 mm high, entire or shallowly 2- or 3-lobed with hemispheric lobes, the surface verruculate. Male flowers of two to six stamens, usually four to six, enlarged in the lowermost part of the male zone where they measure about 5 by 2 mm in cross section; stamens 2-3 mm long; filaments about 1 mm long, 2 mm in the lowermost flowers, largely connate within a flower; anthers 1-1.3 mm long and 1-1.5 mm across, truncate, the pores apical and elongate. Pollen coarsely areolate.²

ECOLOGY:

Found in open bamboo and deciduous forest at about 200 m.²

PROPAGATION:

In three attempts, we have had no luck rooting this species, either in early August or early September. Even with proper timing, this was among the most difficult species to root.

ETYMOLOGY:

From Latin tenuis, “slender,” and stylus: the styles are 3-4 mm long but only 0.6-0.8 mm thick, and their length is one of the two characters that separate the species from every other in the genus.²

NOTES:

1. The species is distinguished by a combination found nowhere else in the genus: an elongate tuber together with very long styles.²

2. The leaf has never been described. The species is known only from flowering material.²

3. The warts lining the base of the spathe recall those of Amorphophallus longituberosus and Amorphophallus albispathus, though in those species they are neither as long nor branched. Those two are its nearest relatives, and all three share a three-chambered ovary and enlarged male flowers at the base of the male zone.²

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus tenuistylis Hett.

2. Blumea 39: 279 (1994) — protologue.

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

4. Propagation of Amorphophallus by Leaf Petiole Cuttings — Juniper Level Botanic Garden