AMORPHOPHALLUS MAYOI
PROTOLOGUE: Amorphophallus mayoi (Ittenb.) Eb.Fisch., B.Dumbo & L.Dumbo, published in Fischer E, Dumbo B, Dumbo L (2022) A new species of Amorphophallus (Araceae) from Eastern D.R. Congo, and a new record of the genus from Rwanda. Plant Ecology and Evolution 155(3): 333-342..
Amorphophallus mayoi (Ittenb.) Eb.Fisch., B.Dumbo & L.Dumbo, comb. et stat. nov. Basionym: Amorphophallus calabaricus N.E.Br. subsp. mayoi Ittenb., Willdenowia 27(1-2): 159. 1997. — Type: UGANDA, Mengo Distr., Kajansi Forest Reserve, 16 m on road to Entebbe; April 1938; Chandler 2433; holotype: K.
SYNONYMS:
HOMOTYPIC SYNONYMS: Amorphophallus calabaricus subsp. mayoi Ittenb. in Willdenowia 27: 159 (1997)
DISTRIBUTION: C. DR Congo to W. Kenya: Kenya, Uganda, DR Congo.
DISTRIBUTION NOTE: Eastern DR Congo (Yangambi), Uganda (Budongo Forest, the Entebbe region and Mbale District), western Kenya (Kakamega Forest) and Rwanda — the first Rwandan record, from the Cyamudongo Forest in Nyungwe National Park, 2019.².
SPECIES DESCRIPTION:
Tuber depressed-globose, 4 cm in diameter. Leaf c. 80-125 cm long; petiole 60-100 cm long, densely covered with confluent spots; lamina 0.8-1.2 m in diameter; rhachises narrowly winged distal from the higher order leaflets; terminal leaflets oval to elliptical, slightly asymmetrical, 6-25 × 2-8 cm, shortly acuminate, margins smooth. Cataphylls 3, oval to elongate, c. 20 cm long.⁴
INFLORESCENCE:
Inflorescence 50-80 cm long, long-peduncled; peduncle 20-63 cm long, 0.8-1.2 cm in diameter, spotted. Spathe erect, 10-20 cm long, separated by a very shallow constriction in a conical tube and a triangular, erect limb; tube 5-7 × 3-4 cm, inside basally with loosely disposed, 1-3(-4) mm long, elongate hairlike emergences, higher up reduced to small papillae; limb 5-13 cm long, purple to brownish; margins smooth or slightly undulate. Spadix sessile, 15-30 cm long, c. 1.5 times as long as the spathe; pistillate zone cylindrical to cubic, 2-2.5 × 0.5-1.3 cm, flowers congested or somewhat distant; staminate zone cylindrical to obconical, 1.5-2.8 × 0.5-1.5 cm, flowers congested; sterile zone between pistillate and staminate zone 0-2 mm long; appendix elongate-conical, 10-25 cm long, 1-3 cm in diameter at the base, purple, smooth. Pistillate flowers 2-3 mm long; ovaries bilocular, globose to ovoid; stigma sessile, slightly bilobed or rarely unlobed, narrower than or equal to the ovaries in diameter. Staminate flowers with anthers free, ovoid to cubic, dark orange; filaments 0-0.4 mm long; pores oval, one apical pore per theca. Infructescence cylindrical, 7 × 2.5-3 cm.⁴
ECOLOGY:
Found in submontane to montane rainforest — in Rwanda under the closed canopy of Newtonia and Entandrophragma forest at 1801 m; altitude across the range: 470-1801 m²
DISTRIBUTION MAPS:
ETYMOLOGY:
Ittenbach dedicated the taxon to the English botanist S.J. Mayo, who revised the Araceae of tropical East Africa.⁴
NOTES:
1. Originally described as a subspecies of Amorphophallus calabaricus, the taxon was raised to species rank in 2022: it differs from Amorphophallus calabaricus in its olive-green upper spathe, an olive-green to yellowish appendix not exceeding 1.5 times the spathe length, and the proportions of the fertile zones — and where Amorphophallus calabaricus is restricted to coastal lowland rainforests of Nigeria and Cameroon at 50-500 m, Amorphophallus mayoi occupies submontane to montane forests of East and Central Africa.²
2. The species is known from at least seven localities, four of them protected as forest reserves or national parks, and has been assessed as Vulnerable.²
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus mayoi (Ittenb.) Eb.Fisch., B.Dumbo & L.Dumbo