AMORPHOPHALLUS FONTARUMII

PROTOLOGUE: Amorphophallus fontarumii Bulawin, Medecilo & Alejandro, published in Nordic Journal of Botany 2022(7)-e03643: 3 (2022).

Amorphophallus fontarumii Bulawin, Medecilo-Guiang & Alejandro, sp. nov.

A miniature species, with dark brownish-red flower to pink inflorescence, elongated triangular-ovate spathe, slightly undulate spathe margin, spadix much longer than spathe, finely verruculose, long, thin and filiform appendix apex, no staminode, cylindric female zone, obconic male zone, globose ovary and irregular peltate stigma with one lobe. Comparable to Amorphophallus caudatus by texture of the petiole, long peduncle, leaf, arrangement of ovaries and male–female zone but different by its irregularly peltate stigma with one lobe, globose ovary, an appendix which is verruculose, nearly smooth at the middle with finely verruculose long, thin and filiform apex, absence of staminode, spathe shape and margin, leaf shape, margin, apex, lamina, tuber and the dimension of the plant. It also resembles Amorphophallus minimus by texture of the petiole, leaf, leaf apex, long peduncle and female zone but is different in its tuber, petiole, rachis, leaflets shape, venation, leaf margin, spathe, spadix, arrangement of ovaries, ovary shape, stigma, male flowers, anther, staminode and appendix (Table 1). The species would be considered one the smallest species of Amorphophallus, at least as compared to other species known from the Philippines.

Type: Philippines, Luzon: Kaliwa Watershed Forest Reserve, Tanay Rizal, 14°42′24.2172″N, 121°22′26.1762″E, 17 Jun 2021, N.F. Bulawin NFB 030, accession numbers 258563/016436 (Holotype: PNH, Isotype: USTH).

DISTRIBUTION: Philippines: Philippines.

DISTRIBUTION NOTE: Amorphophallus fontarumii is known only from Luzon, the Philippines, in Tanay Rizal, Kaliwa Watershed Forest Reserve. It is distributed in the type locality of Mamuyao with 2229 hectares at Kaliwa Watershed Forest Reserve. (Hetterscheid et al. 2012).

SPECIES DESCRIPTION:

Tuber globose, 2–3 cm in diameter, 1–2 cm high, dark or pale brown. Leaf solitary; petiole 27–32 cm long, 0.37–0.44 cm in diameter, its surface smooth, narrowing to the upper part, dark brownish–red to brown or light green, with dark brown and whitish spots from the base to the upper part; lamina 24–30 cm in diameter; rachises narrowly winged in distal part, divided into three leaflets, light green, smooth, ca 3 cm long, 2.85–2.90 mm in diameter; leaflets narrowly elliptic to lanceolate, oblique, equally divided, 2.5–6.8 cm long, 7–12 mm wide with acumen 3–5 mm long, acuminate tip and cuneate base, slightly leathery, their adaxial surface green, abaxial surface pale green, with depressed midrib and impressed lateral veins in 8–13 pairs, brochidodromous secondary veins forming prominent upward loops near the margin; lamina margin entire, undulate, with decurrent leaf attachment. Inflorescence solitary, erect; peduncle 8.2–10.0 cm long, 1.6–2.0 cm in diameter, dark brownish red to pale pink or green, smooth, with dark brown and dark green spots.

INFLORESCENCE:

Spathe elongate triangular–ovate, when spread out narrowly acute, 6.5–8.5 cm long, 2.0–2.5 cm wide, erect, without constriction, at base outside distinctly convolute, dark brownish–red, at the base of bud with whitish and dark brown spots, pale maroon to pink with whitish and reddish spots, with parallel pinkish veins at the base of the flower, inside pale purple to off white, with slightly grooved and very few verrucae; limb outside triangular, undulating, rolled inward; limb of bud dark brownish–red; flower limb off white to pale cream and pinkish at the edge, inside pale purplish–pink, off white to pale cream, undulate, with undulate margin. Spadix sessile, much longer than spathe, 7–8 cm long; female zone cylindric, 7–8 mm long, 4.0–4.9 mm in diameter; female flowers slightly distant, off white to yellow; ovaries globose, 0.90–1.00 mm diam, 0.45–0.50 mm high, off white to yellow, unilocular; style straight upward, 0.40–0.43 mm long, 0.05–0.08 mm in diameter, whitish to pale brown; stigma irregularly peltate, pale to dark brown with one lobe, 0.40–0.50 mm in diameter, 0.01–0.02 mm high; male zone slightly obconical, 1.6–1.8 cm long, 2.5–3.5 mm in diameter; male flower irregular cuboidal-shaped; male flowers slightly congested, slightly distant at the lower part of male zone, yellow to off white; stamen 0.30–0.40 mm long; anther irregular cubical to cuboidal; filament 0.35–0.20 mm long; staminode absent; appendix narrowly elongated, cylindric, acicular, verruculose, 6–8 cm long, 0.94–9.00 mm in diameter above the base; base dilated to slightly conical narrowly elongated cylindric, verruculose from male zone, at the middle narrowly elongated cylindric and nearly smooth, at apex narrowly long thin cylindric and filiform, finely verruculose, dark brownish–red to deep purple. Fruits not observed.

Flowering from May to June.

ECOLOGY:

This species can be found in a mountainous and shaded area on limestone rock with humus or dried leaves in the soil, similar to Amorphophallus natolii

DISTRIBUTION MAPS:

ETYMOLOGY:

The specific epithet is given in honor of Mr Reynaldo Fontarum, the late father of the first author who was instrumental in providing funds for the fieldwork.

NOTES:

1. With an area of occurrence of less than 100 km² and less than 250 mature individuals in the wild, Amorphophallus fontarumii is critically endangered based on IUCN Red List Guidelines (IUCN Standards and Petitions Committee 2019). Only two individuals with flowers and 38 individuals with vegetative parts were found in the area.

The area of KWFR is prone to erosion, landslides and flash floods. About 18% of the forest is considered degraded because of overexploitation of forest resources, timber extraction for lumber, fuelwood, slash-and-burning farming practices and quarrying. In addition, a portion of KWFR is exposed to grassfire during summer and kaingin. Activities done by people decreases the population of Amorphophallus in the forest. Amorphophallus longispathaceus was also found in the locality together with Alocasia heterophylla and Arisaema podophyllum.

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus fontarumii Bulawin, Medecilo & Alejandro

2. Nordic Journal of Botany 2022(7)-e03643: 3 (2022) — protologue.

Additional photos by The Gardening Botanist and Norilyn Fontarum Bulawin