AMORPHOPHALLUS EBURNEUS

PROTOLOGUE:Amorphophallus eburneus Bogner, published in Willdenowia, Bd. 18, H. 2 (Feb. 22, 1989), pp. 441-443.

Amorphophallus eburneus Bogner, sp. nova Typus: Bogner 1772 (holo- M). Foliola elliptica, acuminata vel caudata, viridia, nervis primariis 8-22. Cataphylla aliquot, longissi- mum eorum spathae partem convolutam superans. Inflorescentia breviter pedunculata; spatha albida; spadix cremeus; thecae staminum quaternae usque senae (4-6) connatae, longitudinaliter ordinatae; ovaria oblongi-cylindrica stigmatibus subsessilibus, saepius bilobis.

DISTRIBUTION: Borneo (Sarawak): Borneo.

DISTRIBUTION NOTE: Only known from type collection: Borneo, Sarawak, near Padawang north of Bau.

SPECIES DESCRIPTION:

Whole plant ca. 1.5 m high, leaf compound and ca. 1.4 m across. Tuber over 20 cm in diameter. Petiole to 85 cm long and 4–5 cm in diameter, green. Leaf-blade medium-green, divided in three main parts, rachis at base ca. 2.5 cm thick, above canaliculate, each part divided twice in adult stage; leaflets elliptic, somewhat oblique at base, sessile and long-decurrent on lower side, 12–40 cm long and 5.5–14.0 cm wide, base cuneate, apex acuminate to caudate; leaflet with 8–22 deeply impressed primary lateral veins on each side of the strong middle vein, collecting vein 4–8 mm from the margin.

INFLORESCENCE:

Peduncle ca. 20 cm long and ca. 2.5 cm in diameter; 6 cataphylls up to 35 cm long, the shortest only 3–4 cm long, light reddish green. Spathe ca. 20 cm long, convolute in its lower part, somewhat flared in its upper part, cream-colored, inside at base red and furrowed. Spadix ca. 21 cm long; appendix 14 cm long, cylindric, cream-colored, ca. 1.5 cm in diameter; male part ca. 4 cm long and ca. 1.5 cm in diameter, light brownish; female part ca. 2.5 cm long and ca. 2.0 cm in diameter. Stamens usually connate with clusters of 4–6 thecae; clusters 4–10 mm long and about 1 mm wide, longitudinally arranged; thecae 0.8–1.0 mm in diameter, globular to somewhat ellipsoid, opening by apical pores; pollen grains inaperturate, globular, exine smooth. Ovaries oblong-cylindric, 3.5–4.0 mm long and ca. 2.5 mm in diameter, mostly 2-locular, below light green, above and stylar region red; stigma subsessile, 2-(3-) lobed, 1.5–1.8 mm in diameter, papillose, brownish.

ECOLOGY:

Limestone, 100 m, growing in leaf litter

ETYMOLOGY:

From Latin eburneus, “ivory-colored,” likely referring to the cream- or ivory-colored spathe and spadix appendix.

NOTES:

1. Amorphophallus eburneus belongs to Amorphophallus sect. Conophallus (Schott) Engler (cf. Engler 1911) and differs mostly by its medium-green leaflets with acuminate to caudate apices and 8–22 deeply impressed primary lateral veins on each side; inflorescence short-peduncled, enclosed by several cataphylls, the largest exceeding the convolute part of the spathe; spathe cream-colored; spadix exceeding slightly the spathe; stamens connate in clusters of 4–6 thecae; ovaries oblong-cylindric, stigma mostly 2-lobed.

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus eburneus Bogner

2. Willdenowia, Bd. 18, H. 2 (Feb. 22, 1989), pp. 441-443 — protologue

3. Aroideana 19 (1996): P. 7-131

4. Alan Galloway — Amorphophallus eburneus, alangallowaybotanicals.com

Additional photos and videos by Michael Lo and Steve Jackson