AMORPHOPHALLUS MALKMUS-HUSSEINII
PROTOLOGUE: Amorphophallus malkmus-husseinii A.Galloway, Prehsler & Claudel, published in Aroideana 42(1): 67 (2019).
Amorphophallus malkmus-husseinii A. Galloway, Prehsler & Claudel sp. nov. Type: from a plant cultivated by A. Galloway (orig. coll.: LAOS, Khammouane Province, in shaded areas among limestone boulders, Bjørn Malkmus-Hussein), 13 May 2016, Galloway AGA-2650-01-T (holotype, QBG, spirit collection).
DISTRIBUTION: Laos: Laos.
DISTRIBUTION NOTE: Laos: Khammouane Province — only known from the type locality, where despite an extensive search only one population of roughly 60 specimens could be found².
SPECIES DESCRIPTION:
Tuber depressed globose, 2-2.5 cm in diam., 1-1.5 cm high, brown, annually producing thickened rhizomatous offsets, up to 4 cm long, easily detached from tuber. Leaf solitary; petiole up to 15 cm long, 4 mm in diam. at base, 3 mm in diam. at top, sparsely hairy, pale brownish-green with darker striation at bottom and lighter striation at top; lamina up to 20 cm in diam., rachises 5 mm long; leaflets usually 5, elongate elliptic, acuminate, to 10 cm long, to 4.5 cm in diam., upper side mid green, slightly glossy, lower side pale green with darker green venation.²
INFLORESCENCE:
Inflorescence produced alongside the leaf. Peduncle 20-30 cm long, 4-5 mm in diam.; spathe elongate ovate, erect or recurving at anthesis, to 3.7 cm long, 1 cm in diam. near the base, outside base pale brownish-gray, inside basal part surrounding fertile zone purplish-burgundy, upper parts pale grayish-white with pale brownish-green venation, apex acute. Spadix sessile, ca. 3 cm long, erect; female zone 2 mm long, 2.5 mm in diam., flowers mostly congested; male zone elongate, slightly conical, 11 mm long, 3 mm in diam. at the base, 1.5 mm in diam. at the apex, flowers distant; appendix to 15 mm long, 3 mm in diam. at the base, 1 mm at the apex, elongate conical, base truncate, sterile zone between appendix and fertile zone 3 mm long, 1 mm in diam., recurved forward, pale rosy-white with darker purplish spots, apex obtuse, surface smooth, pale brown. Ovaries few, depressed, ca. 2 × 1 mm in diam., 1 mm high, base white, upper half purplish; style conical, 0.2 mm long, 0.4 mm in diam. at the base; stigma depressed, 0.8 mm in diam., 0.3 mm high, very shallowly bilobed, minutely echinate, pale rosy green. Stamens subglobose, 0.3-0.5 mm in diam., 0.2-0.3 mm high; filaments ca. 0.1 mm long, fused, whitish; anthers long fused, 0.1-0.4 mm high, reddish-purple; pollen rosy purplish. Infructescence more or less globose, berries crowded; berries ovate, truncate, ca. 4 mm in diam., ca. 4-5 mm long, bilobed, slightly contracted between the seed-containing locules, surface rugulose, pale yellowish-green with reddish punctation, 2-seeded; seeds globose, 3 mm in diam., mid green.²
ECOLOGY:
Found in small rock cracks in limestone boulders in shade under the canopy of trees, on steep slopes and vertical rocks where landslides are a recurring phenomenon²
ETYMOLOGY:
Named in honour of Bjørn Malkmus-Hussein, horticulturist of La Orotava, Tenerife, who discovered the species in 2015.²
NOTES:
1. Amorphophallus malkmus-husseinii belongs to the Pulchellus-clade of Laotian dwarf species — with Amorphophallus claudelii, Amorphophallus myosuroides, Amorphophallus ongsakulii and Amorphophallus pulchellus — one of two clades of dwarf species revealed by large-scale phylogenetic analysis, characterized by long-peduncled inflorescences whose infructescences bend towards the ground at maturity.⁴ It differs from all other members of the clade in having a sparsely hairy petiole.²
2. Its inflorescence resembles that of Amorphophallus ongsakulii, whose highly dissected, fern-like lamina — possibly a case of mimicry against herbivory — contrasts with the simple five-leaflet leaf of Amorphophallus malkmus-husseinii. Seedlings raised from the species show the same leaf architecture and floral morphology with no intermediate characters, ruling out a hybrid origin.²
3. The Laotian dwarf species are among the more attractive ornamental members of the genus: they are easily grown in small pots, multiply well by offsets and flower freely; tubers should be stored dry in soil during dormancy.²
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus malkmus-husseinii A.Galloway, Prehsler & Claudel
2. Aroideana 42(1): 67 (2019) — protologue.
3. Alan Galloway — Amorphophallus malkmus-husseinii, alangallowaybotanicals.com.
4. Large-scale phylogenetic analysis of Amorphophallus (Araceae) derived from nuclear and plastid sequences reveals new subgeneric delineation. Botanical Journal of the Linnean Society 184: 32-45 (2017)