AMORPHOPHALLUS FERRUGINOSUS
PROTOLOGUE: Amorphophallus ferruginosus A.Galloway, published in Aroideana 35: 58 (2012).
Amorphophallus ferruginosus Alan Galloway sp. nov. Type: from a plant cultivated by A. Galloway (orig. coll: LAOS, Khammouane Province, in shaded areas in pockets of soil on top of limestone boulders, A. Galloway), 25 March 2011, Galloway AGA-2199-01-T (holotype, QBG, spirit collection.). Figures 13–16.
DISTRIBUTION: Laos: Laos.
DISTRIBUTION NOTE: LAOS, Khammouane Province.
SPECIES DESCRIPTION:
Tuber depressed globose, entirely covered with thick, short protrusions, sometimes associated with root-scars, rust-colored, 6–8 cm in diam., 4–5 cm high, with several large, elongate fusiform offsets 2–3 cm long, 3–5 mm wide. Leaf solitary; petiole 30–36 cm long, 2–2.5 cm in diam., longitudinally ridged, rust-colored, sometimes with several rhombic or elliptic-elongate, pale creamish spots; lamina moderately to highly dissected, up to 110 cm wide, rachises broadly winged except the basal branching points; leaflets elliptic, tip acuminate, base broadly decurrent, 7.5–25 cm long, 3.5–7.5 cm in diam., upper side green to olive-green, lower side paler with a faint purplish flush.
INFLORESCENCE:
Inflorescence solitary, long pedunculate; peduncle as petiole, 8–10 cm long, 0.75–1 cm in diam.; spathe erect, triangular, base convolute, top acuminate, 8.5–9 cm long, 5–6 cm in diam., outside basal part faintly rust-colored, upper part white with some faint reddish venation, inside basal part faintly flushed pink, upper part white, base inside smooth. Spadix shorter than or equal to spathe, sessile, 8–9 cm long; female zone cylindric, 1 cm long, 1 cm in diam., flowers congested; male zone cylindric, 2 cm long, 1.2 cm in diam., flowers congested; appendix elongate conic, top obtuse, 5 cm long, base 1 cm in diam., upper part 0.5 cm in diam.
Ovaries obovoid to globose, angulate, ca. 1 mm in diam., reddish purple, unilocular; style ca. 0.5 mm long, ca. 0.2 mm in diam.; stigma depressed, entire, ca. 0.2 mm high, 0.5 mm in diam., verrucate, pale yellow. Male flowers consisting of (1–)2–3 stamens; stamens 1–2 mm long; filaments indistinct in upper part of male zone or entirely fused into a column, ca. 1 mm long in lower part of male zone; anther truncate, ca. 1 mm long, ca. 1 mm in diam., off white; pore apical, ovate to round.
ETYMOLOGY:
From Latin ferruginosus, “rust-colored” or “ferruginous,” referring to the distinctive rusty-brown coloration of the tuber surface and petiole.
NOTES:
1. The tuber of Amorphophallus ferruginosus is covered with thick, short protrusions, more pronounced than those found on the tubers of Amorphophallus bolikhamxayensis Alan Galloway, A. Ongsakul & P. Schmidt (this publication) and Amorphophallus tuberculatus Hett. & V. D. Nguyen (N. Vietnam). The rust coloration of the exterior of the tuber is nicely matched by the more intense rust coloration of the petiole. The inflorescence of Amorphophallus ferruginosus has a morphological resemblance to Amorphophallus schmidtiae Hett. & Alan Galloway (Laos), with the exception being the color of the ovaries, reddish purple in Amorphophallus ferruginosus and pale green in Amorphophallus schmidtiae.
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus ferruginosus A.Galloway
2. Aroideana 35: 58 (2012) — protologue.
3. Alan Galloway — Amorphophallus ferruginosus, alangallowaybotanicals.com.
Additional photos by Alexander Egan, Craig Allen and Jeremiah Baer