AMORPHOPHALLUS PROLIFICUS
PROTOLOGUE: Amorphophallus prolificus Hett. & A.Galloway, published in Aroideana 29: 69 (2006).
Amorphophallus prolificus Hett. & A. Galloway, sp. nov. Type: from a plant cultivated in the Botanical Gardens of Wageningen University (orig. coll.: THAILAND, central, precise data unknown, A. Galloway), 30 June 2005, Hetterscheid H.AM.1245-T (holotype, WAG, spirit collection).
DISTRIBUTION: C. Thailand: Thailand.
DISTRIBUTION NOTE: Thailand: central Thailand, without precise locality; known only from the type gathering.².
SPECIES DESCRIPTION:
Tuber globose, 2-3.5 cm in diam., 1.8-3 cm high, smooth, pale to mid brown, producing annual, large, globose to fusiform offsets, these 1.5-2.2 cm in diam., 2.3-3 cm long, remaining attached to the main tuber. Petiole 15-35 cm long, 4-8 mm in diam., smooth, uniformly greyish purple or dirty dark olive-green; lamina 16-40 cm in diam., rachises winged distal from the basal branchings, segments moderately divided; leaflets obovate to elongate obovate or elongate-elliptic, 7-18 cm long, 4.3-7.5 cm in diam., apex acute, upper surface green.²
INFLORESCENCE:
Peduncle 20 cm long, 0.5 cm in diam., smooth, uniformly dark greyish brown; spathe erect, not separated into base and limb, transversely elliptical, 5 cm long, 8 cm wide, apex hardly distinguishable, very broadly acute, margin strongly concave, outside white with a greenish flush, base slightly greener, inside pale green, base with a very indistinct, very pale purplish flush, base within densely set with shallow, irregular warts. Spadix longer than spathe, sessile, 10.5 cm long; female zone cylindric, 7 mm long, 8 mm in diam., flowers distant and set in distinct pockets sunk into the spadix axis; male zone cylindric, base slightly constricted, 3 cm long, 1 cm in diam., flowers congested but in the lower part slightly separated into smaller and larger multi-staminate groups; appendix elongate conical, 6.8 cm long, 13 mm in diam. near the base, basal part slightly laterally compressed, apex acute, surface smooth to very shallowly rugulose, emitting a strong smell of oligomethyl-oligosulphides. Ovary subglobose, 1.5 mm high, 1.8 mm in diam., unilocular, pale green; style short, 0.5 mm long, 1 mm in diam., pale green; stigma large, depressed, entire, 2-2.5 mm in diam., verruculate, white. Lower male flowers consisting of (2-)5 to about 10 stamens, the upper flowers seemingly of ever more stamens and then turning into a continuous zone; stamens 1 mm long, 1 mm in diam.; filaments 1 mm long, off-white, free; anthers 0.8 mm long, truncated, off-white, the apical pores fused to form one central pore per anther. Pollen psilate.²
ETYMOLOGY:
From Latin prolificus, “prolific”: the epithet records how freely the plant multiplies by itself. Each year the tuber throws large globose to fusiform offsets which stay attached to it, so a single plant becomes a cluster.²
NOTES:
1. Diagnosis: in the incurved spathe margin it closely resembles the Amorphophallus saururus group - Amorphophallus operculatus, Amorphophallus pygmaeus, Amorphophallus saururus, Amorphophallus vogelianus and others - but differs from them in a pollen-release mechanism belonging instead to the Amorphophallus brevispathus alliance: at anthesis the two adjacent thecae of a single stamen shed pollen through one shared pore, after the thin connective has ruptured completely. No species of that alliance has the incurved spathe margin.²
2. The tuber and the leaf both recall Amorphophallus brevispathus, and it shares that alliance's pollen-release mechanism, while the spathe recalls the Amorphophallus saururus alliance instead. Tuber and leaf are similar again in Amorphophallus atrorubens.²
3. The appendix gives off a strong smell of oligomethyl-oligosulphides at anthesis.²
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus prolificus Hett. & A.Galloway
2. Aroideana 29: 69 (2006) — protologue.
3. Alan Galloway — Amorphophallus prolificus, alangallowaybotanicals.com.
Additional photos by Marco Motta