Amorphophallus rayongii Hett. & Medecilo, 2020

Hetterscheid, W. L. A., Medecilo, M. P., Callado, J. R. C. & Galloway, A., 2020, New species of Amorphophallus (Araceae) in the Philippines and an updated key, Blumea 65 (1), pp. 1-9 : 4-7

3. Amorphophallus rayongii Hett. & Medecilo , sp. nov. — Plate 3

Etymology. The species is named after Ray Ong, who discovered it on Boracay island.

Type. G. Yao s.n. (holo PNH 256730 ), Philippines, Boracay Island , Malay , Aklan, along vacant lots near the resort shoreline, 20 May 2012 .

Tuber irregularly globose, to at least 8 cm diam, producing few offsets, released in next growing season after initiation. Petiole 35 by 0.8 cm, smooth, pale green, upper part with scattered, whitish spots, lower part with indistinct olive green spots. Lamina 70 cm diam, rachises very narrowly winged throughout; leaflets elongate elliptic, 4–19 cm long, 1.5–5 cm wide, acuminate. Peduncle c. 100 cm long, c. 2.5 cm diam, smooth, pale green. Spathe elongate triangular, 23.5 cm long, 12 cm wide (base), base and limb separated by a constriction, base outside green, inside upper part green, lower part maroon, limb erect, outside pale brown, inside dark brown, base inside densely verrucate. Spadix longer than spathe, 52.5 cm long; female zone cylindric, 2 cm long, 1.7 cm diam, flowers congested; male zone 10.5 cm long, 1.8 cm diam, flowers congested; sterile zone between female and male zone 1 cm long, 1 cm diam, with slightly separated synandrodes; appendix narrowly elongate conical, 39 cm long, 2 cm diam at the base, gradually tapering to the subacute top, surface rugulose, pale green or off-white. Ovaries depressed, 4 mm diam, 2 mm high, pale green, unilocular; style 1–2 mm long, 1 mm diam, curved upwards, pale green; stigma depressed or transversely bilabiate, 3 by 1.5 mm diam, 0.8 mm high, more or less strongly 2–3-lobed, surface verrucate, pale brown. Male flowers consisting of 4–5 stamens; stamens 2 mm long; filaments very short, free, c. 0.2 mm long; anthers off-white, subtruncate, 1.8 mm long, 2 mm diam, connective slightly sunken, pores apical, slit-like. Synandrodes elliptical, 4–7 mm long, 3–4 mm diam, 2 mm high, flattened, surface densely verrucate or irregular.

Distribution — Known only from the type locality.

Notes — Amorphophallus rayongii is morphologically very close to A. salmoneus , with which it shares the flattened, verrucate synandrodes between the male and female zone. No other species on the Philippines show this character. It is not a unique character in the genus and is found in quite a number of species from SE Asia, although the verrucate surface of the Philippine species is unique.

Amorphophallus salmoneus has been placed in subg. Amorphophallus ( Claudel et al. 2017) close to A. dactylifer and A. declinatus both Philippine species. This subclade is part of a larger clade with exclusively insular SE Asian species from Indonesia and East Malaysia. However, all other species with synandrodes similar to those of A. salmoneus and A. rayongii are part of subg. Scutandrium Hett. & Claudel, dominated by mainland SE Asian species. The synandrodes therefore are clearly a parallel expression developed from fertile male flowers in different clades.

Figures

Plate 3 Amorphophallus rayongii Hett. & Medecilo (plant cultivated in the Philippines). a. Inflorescence; b. leaf; c. spathe cut open exposing larger part of the spadix; d. lower part of the spadix showing basal female zone and part of the male zone with in between the staminodial zone. — Photos by: R. Ong.