Amorphophallus fornicatus Hett., J.R.C.Callado

1. Amorphophallus fornicatus Hett., J.R.C.Callado View in CoL & Wistuba, sp. nov. — Plate 1 View Plate 1

Etymology. The species epithet refers to the shape of the spathe limb.

Type. J.R.C. Callado JRCC 982 (holo PNH 256728 ), Philippines, Luzon , Quezon National Park, Atimonan , 26 July 2013 .

Tuber globose, 4–5 by 4–5 cm, white, with one (or more?), globose offset, the latter c. 1 cm diam. Leaf solitary; petiole 43–55 by 1–1.5 cm, smooth, uniformly pale green or rarely with very few whitish spots near the base; lamina 45–65 cm across, moderately dissected, an epiphyllar bulbil developing in the centre, this depressed globose, verrucate, c. 1 cm diam, rachises not winged; leaflets elliptic to elongate elliptic, 3–19 cm long, 1–7 cm across, acuminate, slightly leathery, upper surface glossy mid green, lower surface dull pale green. Inflorescence short pedunculate; peduncle 1–2 cm long, entirely hidden in the soil, stretching to twice its length during fruiting. Spathe ovate when spread out, 19– 20 cm long, 10–11 cm diam at the base of the limb, erect, basal part strongly convolute, tubular, limb fornicate, overtopping the spadix, acute, opening wider at male anthesis with margins reflexing, base outside off-white or pale green with whitish orbicular spots, with or without a purplish, white-maculated margin, inside basal part pale purplish, with a few larger verrucae or slightly grooved, upper part off-white. Limb outside whitish green or with a pale purplish background but largely hidden by large, strongly confluent whitish spots, inside deep purplish with numerous, small whitish spots, less numerous towards the margin. Spadix sessile, shorter than spathe, 12–13.5 cm long; female zone cylindric, 1.5–1.7 cm long, 1.6 cm diam, pistils congested; male zone obconic, 4.5–5 cm long, 1.6–1.8 cm diam at the base, 2.2–2.3 cm diam at the top, base and top truncated; appendix stipitate (stipe 0.3–0.5 cm long, grooved or with very flattened, elliptical staminodes), narrowly to broadly elongate conical, 7.5 cm long, 4 cm diam, obtuse, dark purple, surface strongly echinate-papillate, echinae (staminodes) fleshy, narrowly conical, c. 1 mm long, shorter near the top, acute or obtuse. Ovary depressed, 1 mm long, 2 mm diam, unilocular, blackish purple; style curved upwards, 1–1.5 mm long, 0.8 mm diam, ridged, blackish purple; stigma thin, whitish, transversely bilabiate to irregularly stellate, 2-, 3- or multilobed, to 1.3 mm diam, lobes conical. Male flowers consisting of 3 stamens; stamens 2 mm long; filaments almost free to the base 1 mm long, 0.7 mm diam, anthers halter-shaped in cross-section, 1 mm long, c. 1 mm diam, pale pinkish; thecae subglobose, top subtruncate to obtuse, separated by a deep, groove-like connective, pores apical, elliptic. Infructescence cylindric; berries ovate, c. 9 mm long, c. 8 mm diam, smooth, orange; seeds c. 7 mm long, c. 4 mm diam.

Distribution — Philippines, Luzon, Quezon National Park, Atimonan.

Note — The shape of the spathe of A. fornicatus and the echinate appendix are unique compared to all species of the genus in Asia. In both characters it shows a remarkable similarity to the West African A. dracontioides (Engl.) N.E.Br. The narrow spathe base and several characters of the female and male zone, and the pistils and anthers are reminiscent of A. hottae Bogner & Hett. from Sabah (eastern Malaysia). The leaf is also similar to that of the latter species, up to the formation of epiphyllar bulbils.