AMORPHOPHALLUS MINIMUS
PROTOLOGUE: Amorphophallus minimus R.Bustam., Claudel & M.N.Tamayo, published in Nordic J. Bot. 2021: e03251 (2021).
Amorphophallus minimus R.Bustam., C. Claudel and M.N.Tamayo, sp. nov. (subg. Amorphophallus) Type: Philippines, Luzon, Province of Nueva Ecija, Municipality of Carranglan, in shaded areas of dipterocarp forest near stream, Pantabangan-Carranglan Watershed Forest Reserve, 950-1400 m a.s.l., 14 Jun 2019, PTI 0006 with L. Udasco (holotype: PNH, isotype: CAHUP).
DISTRIBUTION: Philippines: Philippines.
DISTRIBUTION NOTE: Philippines: Luzon — Nueva Ecija, the Pantabangan-Carranglan Watershed Forest Reserve, where three populations are known².
SPECIES DESCRIPTION:
Tuber depressed globose, 1.0-2.5(-3.0) cm in diameter, 1-2 cm high. Leaf solitary. Petiole 10-40 cm × 5-7 mm, smooth; background color rust-colored to dark green with pale green lichenous patches and sporadic dark green spots; markings elongate-elliptic, circular or irregular in shape, pale green. Leaf bulbils half-epiphyllar to epiphyllar, obpyramidal, 1.0-1.5 cm. Rachis winged distally starting from the second branching; basal part naked with few sub-petiolate leaflets. Leaflets elliptic-lanceolate or oblanceolate, 2.5-10.5 cm × 0.8-3.2 cm, with entire margin, slightly undulate, acuminate (acumen 5-15 mm long); lateral veins 5-10 pairs, adaxially sunken.²
INFLORESCENCE:
Inflorescence solitary; peduncle smooth, almost the same coloration and marking as petiole, 12.5-20.5 cm × 5.0-6.0 mm; spathe fornicate or nearly so, 9.0-12.0 cm × 4.7-5.0 cm, acute triangular (when spread), with entire margin, smooth, membranaceous, strongly convolute at base, with limb narrow and arching over, tubular; outside of spathe maroon near edges turning brown with scattered white spots towards limb; limb maroon with a tinge of brown or green with sporadic white spots; inside of spathe light maroon to claret near margin with sporadic white spots, turning whitish towards the base, smooth. Spadix sessile, shorter than the spathe, 5.6-6.8 cm × 7.0-8.0 mm. Appendix staminodes colliculate all over, elongate-clavate, 2.5-2.7 cm × 5.0-8.0 mm; more or less constricted near the male zone; pale red, maroon or purplish. Female zone cylindric, 0.8-1.4 cm × 6.0-7.0 mm; flowers congested. Ovaries green, depressed globose to subglobose, 1.5-1.8 mm × 1.2-1.5 mm, unilocular. Style reddish, short, 0.5-0.7 mm × 0.6-0.9 mm. Stigma reddish, 0.4-0.5 mm × 0.4-0.5 mm, minutely and irregularly (2-)3-5-lobed, lobes rounded or conic, their surface minutely papillate. Male zone contiguous with the appendix, elongate, 2.0-2.7 cm × 4.0-6.0 mm, with slightly congested white to pale yellow flowers. Male flowers consisting of a pair of fused stamens arranged in a cluster. Stamens two per flower, white to pale yellow, 0.5-0.7 mm × 0.4-0.5 mm, oblate at apex. Filaments thick, 0.5-0.6 mm long, connate. Anthers 0.2-0.3 mm, oblong, bilocular, truncate; pores apical, fused in slits. Fruits not observed.²
ECOLOGY:
Endemic to montane forest at 950-1400 m, on steep inclines of 70-85° in dipterocarp forest and/or secondary forests, always within close proximity to water sources such as rivers or streams; forest litter is typically heavy in its habitat, and plants remain comparatively dry and inactive during the dry season (December-May)²
DISTRIBUTION MAPS:
ETYMOLOGY:
From Latin minima, "small" — the name depicts the relatively small size of both the vegetative and flowering phases.²
NOTES:
1. The inflorescence of Amorphophallus minimus has an overall resemblance to that of Amorphophallus palawanensis, but differs by its club-shaped (clavate) appendix with a colliculate surface, a contiguous male zone and appendix, two stamens per flower, and oblate stamens; it also forms leaf bulbils, a trait not observed in Amorphophallus palawanensis.²
2. The species is the 17th Amorphophallus endemic to the Philippines, and its discovery suggests that more await discovery in the remaining pristine forests of the country.²
3. A preliminary conservation status of Critically Endangered has been proposed.³
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus minimus R.Bustam., Claudel & M.N.Tamayo
2. Nordic J. Bot. 2021: e03251 (2021) — protologue.