AMORPHOPHALLUS DZUI
PROTOLOGUE: Amorphophallus dzui Hett., published in Blumea: Biodiversity, Evolution and Biogeography of Plants, Volume 46 - Issue 2 p. 260.
Amorphophallo subpedato similis, appendice parte mascula non latiore, staminodiis inter partes masculas et femineas gaudenti differt
Typus: Hetterscheid H.AM.523-T (holo L, spirit coll.), N Vietnam, Ninh Binh prov., Cuc Phuong National Park (coll. from a plant cultivated in the Leiden Bot. Garden, orig. coll. V.D. Nguyen s.n.).
DISTRIBUTION: Vietnam: Vietnam.
DISTRIBUTION NOTE: N Vietnam, known only from the type locality.
SPECIES DESCRIPTION:
Tuber shortly elongate, broad, 10 cm diam. at the top, c. 20 cm long, branched in the lower half. Petiole 19-24 cm long, 1-1.5 cm diam., smooth, pale green to whitish green; lamina 60-90 cm diam., rachises largely unwinged; leaflets elongate oblong, acute-acuminate, to 24 cm long, 6-8 cm diam., leathery, margin more or less strongly undulate, upper surface glossy green, lower surface moderately glossy pale green.
INFLORESCENCE:
Inflorescence solitary, long (and short?) peduncled; peduncle (3-)9 cm long, 5-10 mm diam., smooth, greyish green; spathe broadly triangular, broader than long, 3-9 cm long, 4-11.5 cm diam., convolute, limb strongly reduced, strongly clasped around the male zone during anthesis, top obtuse, separated from the base by a very shallow constriction or not, base outside greyish green or pale grey with or without dark grey small spots and blackish veins, the margin pale grey, inside blackish maroon, the base a little paler, limb outside dark greyish or dark brownish purple, inside paler and spotted dark maroon, base within smooth or grooved. Spadix much longer than spathe, sessile, 14.5-26 cm long; male zone extending well beyond the spathe; female zone cylindric, 0.5-2.5 cm long, 0.7-1.7 cm diam., flowers congested; male zone cylindric, 4-8.5 cm long, 0.7-1.8 cm diam., flowers congested, or slightly distant; sterile zone between male and female zone 0.5-1.5 cm long, 0.7-2.2 cm diam., staminodes congested; appendix narrowly conical, slightly or distinctly constricted at the base, 9.5-13 cm long, 1-2.2 cm diam. near the base, acute, smooth or shallowly rugulose, offwhite. Ovaries depressed, irregularly angulate-lobate in cross section, 2 mm diam.,1 mm high, narrowed to the base in a short pedicel, pale green, top flushed maroon, unilocular; style short, thick, conical, c. 0.5 mm long, c. 1 mm diam., pale green or flushed maroon; stigma depressed, 1.2-2 mm diam., c. 0.6 mm high, trilobed, lobes conical, resulting in obtuse undulations of the margin. Male flowers consisting of 4-6 stamens; stamens 1-1.5 mm diam., 1.2-2 mm long filaments 0.2-0.8 mm long; anthers truncated, c. 1 mm long, off-white, the connective much broadened, almost rhombic, distinctly raised, orangish, remaining prominent after male anthesis; pores aligning the margin of the connective, laterally connected to form one half-moon-shaped pore per anther, laterally displaced after anthesis; pollen striate, ellipsoidal (length/breadth 1.64), 67 μm long. Staminodes depressed, irregular in cross section, 1.5-4 mm diam., c. 1.4 mm long, the lowest ones small, the upper ones large and with distinct grooves, representing the outline of the once anthers, off-white, smooth or shallowly rugulate.
Infructescence ripening can take up to 18-19 months as reported by Alan Galloway
ETYMOLOGY:
The species epithet refers to Mr. Nguyen Van Dzu (IEBR, Hanoi), whose studies of the Araceae of Vietnam and fieldtrips have yielded invaluable information on Vietnamese Amorphophallus.
NOTES:
1. Amorphophallus dzui resembles closely Amorphophallus subpedatus Hett. & V.D. Nguyen (N Vietnam). The latter has a very distinct subpedate leaf form, upper leaflet surface not glossy, no staminodes between male and female zone, stigmas half the size and an appendix much broader than the diameterof the male zone.
2. Alan Galloway repeatedly reported that this species often produces multiple inflorescences at once
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus dzui Hett.
2. Blumea: Biodiversity, Evolution and Biogeography of Plants, Volume 46 - Issue 2 p. 260 — protologue.
3. Alan Galloway — Amorphophallus dzui, alangallowaybotanicals.com.