AMORPHOPHALLUS VERTICILLATUS
PROTOLOGUE: Amorphophallus verticillatus Hett., published in Blumea 39: 279 (1994).
33. Amorphophallus verticillatus Hett., spec. nov. Ab omnibus speciebus in foliis coaetaneis, spadice spatha equanti, floribus masculis in verticillis disjunctis differt. - Typus: Anonymous (LX-VN) 1727 (LE holo), Vietnam, Prov. Ha Nam Ninh, Cuc Phuong, 1-v-1985.
DISTRIBUTION: Vietnam: Vietnam.
DISTRIBUTION NOTE: Vietnam: Cuc Phuong in the former Ha Nam Ninh province, and Muong Thon in Hoa Binh province.².
SPECIES DESCRIPTION:
Tuber shortly rhizomatous, apparently, 3-4 cm long and 1-2 cm across. Leaves two to a tuber; petiole slender, 13-28 cm long and 3-4 mm across. Lamina moderately dissected, about 30 cm across, the rachises unwinged; the main segments carrying two or three leaflets; leaflets elliptic-oblong or oblanceolate, 7-14 cm long and 2.5-5.5 cm across, broadly acuminate with an apiculate acumen, the base unequally wedge-shaped.²
INFLORESCENCE:
Inflorescence long-peduncled and appearing together with the leaves; peduncle slender, 18-19 cm long and 3-4 mm across. Spathe erect, narrowly elongate triangular, boat-shaped, acute, 8-9.5 cm long and about 2.5 cm across, the base within smooth or very shallowly warted. Spadix sessile, slightly shorter than the spathe, 7-8 cm long; female zone cylindric or conic, 0.5-1 cm long and 0.4-0.8 cm across at the base, the flowers apart or congested; male zone cylindric, 2.5-3.5 cm long and 0.5 cm across, the lowest flowers free or irregularly linked and the rest set in oblique whorls about 5 mm across, separated by naked gaps about 1.5 mm long; appendix more or less cylindric and somewhat obtuse, 4-4.5 cm long and about 0.5 cm across, smooth in the lower quarter and distinctly warted above, the warts broadly conic and obtuse, irregularly joined sideways or separated by grooves and more or less following the arrangement of the male flowers. Ovaries depressed, circular or angular in cross section, 2-3 mm across and about 1 mm high, one-chambered; style short, about 0.4 mm long, conic; stigma circular or oval in cross section, about 0.8 mm across and 0.4 mm high, shallowly 2- or 3-lobed. Male flowers of about four stamens, though the exact number is usually obscured by extensive lateral fusion; stamens 1.5 mm long; filaments 1 mm long, connate only with the facing sides of the adjacent stamens in the whorl; anthers truncate, 0.5 mm long and about 1 mm across, the pores apical, rounded or oval at anthesis. Pollen striate.²
PROPAGATION:
In our single attempt with this species, we achieved 100% rooting from mid-November cuttings. With proper timing, this was among the species that rooted at the highest percentages in the trials.
ETYMOLOGY:
From Latin verticillus, “whorl.” The male flowers are not scattered over the zone but set in distinct oblique whorls, each ring separated from the next by a naked gap.²
NOTES:
1. Three characters together separate it from every other species: leaves and inflorescence appearing at the same time, a spadix about equalling the spathe, and male flowers in discrete whorls.²
2. The warts on the appendix follow the arrangement of the male flowers below them, so the whorling is echoed above the fertile zone.²
3. In general build it comes close to Pseudodracontium, but has a much thinner and less elaborately structured appendix. Pseudodracontium has since been sunk into Amorphophallus.²
4. Male flowers linked sideways also occur in Amorphophallus interruptus, but there the chains are not regular whorls - they are often broken or partly spiralled - and that species is much larger, with a bigger leaf and a spadix far longer than the spathe.²
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus verticillatus Hett.
2. Blumea 39: 279 (1994) — protologue.
3. Alan Galloway — Amorphophallus verticillatus, alangallowaybotanicals.com.
4. Propagation of Amorphophallus by Leaf Petiole Cuttings — Juniper Level Botanic Garden