AMORPHOPHALLUS RUGOSUS

PROTOLOGUE: Amorphophallus rugosus Hett. & A.Lamb, published in Blumea 39: 274 (1994).

Amorphophallus rugosus Hett. & A.L. Lamb, spec. nov. Ab Amorphophallus pendulo Bogner & Mayo in dimensionibus multo maioribus, petiolo ruguloso, appendice erecta rugulosa spatha subaequanti differt. - Typus: Lamb & Surat ALFS 625 (L holo), Malaysia, Sabah, Interior Zone, Tambruan/Keningau District boundary, Ulu Apin Apin, in colluvial soil, on slope of sandstone ridge, cool shaded habitat, alt. c. 700 m, i-1993.

DISTRIBUTION: Borneo (Sabah): Borneo.

DISTRIBUTION NOTE: East Malaysia: Sabah - Ulu Apin Apin, on the Tambunan / Keningau district boundary in the Interior Zone, at c. 700 m; known only from the type collection.².

SPECIES DESCRIPTION:

Tuber depressed globose, c. 20 cm in diam. Leaf unknown.²

INFLORESCENCE:

Inflorescence long peduncled; peduncle c. 45 cm long, c. 2.5 cm in diam. at the base, slightly rugulose at the base, otherwise smooth, background colour whitish, at the base densely and irregularly marbled with dark greyish green, upwards mixed with purple; spathe elongate triangular, base convolute, limb erect but the upper part arching, c. 36 cm long, c. 14 cm in diam., base outside pale pinkish with small dark purple and purple-green or whitish spots, inside purple, upwards turning pinkish cream, limb outside purple, inside basally pinkish cream, the margin and upper part purple with scattered small creamish spots. Spadix slightly longer than spathe, sessile; female zone c. 2 cm long, c. 1.5 cm in diam., strongly oblique, flowers congested; male zone cylindric, top subtruncate, 6 cm long, c. 2 cm in diam., flowers congested and for the greater part vertically aligned and fused, separated by furrows; appendix elongate fusiform-conic, c. 36 cm long, c. 2 cm in diam., base constricted, apex acutish, surface strongly rugulose, dark purple with a narrow whitish zone at the base. Ovaries elongate, c. 3 mm long, c. 2 mm in diam., dark purple, unilocular; style short and thick, 0.2 mm long, 0.5 mm in diam., dark purple; stigma conic or flattened in longitudinal section, shallowly or prominently 2- or 3-lobed, 1-1.3 mm in diam., 0.8-1 mm high, surface rugulose, lobes shallowly or prominently conic, subacute. Male flowers consisting of 4 or 5 stamens; stamens c. 1 mm long; filaments c. 0.2 mm long, entirely connate, creamish; anthers quadrangular or irregular in cross section, c. 1 mm in diam., c. 0.8 mm long, truncate, dirty brownish; pores elongate, apical. Pollen striate.²

ECOLOGY:

Found in colluvial soil on the slope of a sandstone ridge, in a cool shaded habitat; altitude: c. 700 m²

ETYMOLOGY:

From Latin rugosus, “wrinkled”: the epithet refers to the surface of the appendix, which is strongly rugulose, and the petiole is finely wrinkled at the base as well.²

NOTES:

1. Diagnosis: it differs from Amorphophallus pendulus in its much greater dimensions, a rugulose petiole, and an erect rugulose appendix about equalling the spathe.²

2. Amorphophallus rugosus resembles Amorphophallus costatus, described in the same paper, but differs markedly in the much longer peduncle and in being larger throughout.²

3. The leaf has never been described - the species is known only from the type collection, made in Sabah in January 1993.²

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus rugosus Hett. & A.Lamb

2. Blumea 39: 274 (1994) — protologue.