AMORPHOPHALLUS PYGMAEUS

PROTOLOGUE: Amorphophallus pygmaeus Hett., published in Blumea 39: 271 (1994).

Amorphophallus pygmaeus Hett., spec. nov. Ab Amorphophallus parvulo Gagnep. in appendice breviore, stigmatibus hemisphaericis et ab Amorphophallus brevispatho Gagnep. dimensionibus generatim minoribus, spadice spatha tantum parum longiore differt. - Typus: Hetterscheid H.AM.104-T (L holo; spirit coll.), 16-x-1993, cult. Hort. Bot. Leiden ex Thailand, Prachuap, Kirikun (orig. coll. J.R. Shelton, 1971).

DISTRIBUTION: Thailand: Thailand.

DISTRIBUTION NOTE: Thailand: Prachuap Khiri Khan Province - Sam Roi Yot, in crevices of limestone rock at 200-500 m, and the type material from Kirikun.².

SPECIES DESCRIPTION:

Tuber shortly elongate, or globose. Leaf solitary; petiole smooth, 10-40 cm long, 0.5-1 cm in diam. at the base, uniformly reddish brown or pale olive brown; lamina moderately dissected, 10-25 cm in diam., rhachises narrowly winged only in the distal branches; leaflets elliptic-lanceolate, obovate or oblong, base long or short decurrent or constricted, 3-10 cm long, 1-6 cm in diam., upper surface very dark velvety green, lower surface flushed with purple-red.²

INFLORESCENCE:

Inflorescence solitary, long peduncled; peduncle as petiole but longer, 18-36 cm long, 0.5-0.8 cm in diam. at the base; spathe triangular, base shortly convolute and with rather strongly concave sides, top acute, 1.5-6 cm long, 1.5-4 cm in diam., outside and inside creamy white or pinkish white, base within dirty brownish red and with scattered or numerous fleshy, shortly elongate, irregularly branched or laterally flattened warts. Spadix sessile, longer than spathe, 5-8 cm long; female zone shortly cylindric, 0.5-0.8 cm long, 0.4-0.5 cm in diam., flowers congested or slightly distant; male zone fusiform, fusiform-obconic or slightly conic, 2-3 cm long, 0.4-0.9 cm in diam., flowers congested; appendix elongate-fusiform, smooth, very pale green or creamy white, top obtuse, 2.5-4 cm long, 0.4-0.9 cm in diam., producing a heavy gaseous smell at female anthesis. Ovaries depressed, diamond-shaped, angulate or circular in cross section, 2.5 mm in diam., 1-1.4 mm high, pale green, unilocular; style short, 0.3-0.7 mm long, c. 1 mm in diam., pale green; stigma hemispheric or flattened, slightly angulate in cross section, 1-1.8 mm in diam., 0.5 mm high, very shallowly multilobed and with a shallow central depression.²

ECOLOGY:

Found in crevices of limestone rock; altitude: 200-500 m²

PROPAGATION:

Of our five attempts with this species, three resulted in 100% rooting. One attempt with this species in very early August only resulted in 74.2% rooting. With proper timing, this was among the species that rooted at the highest percentages in the trials.

ETYMOLOGY:

From Greek pygmaios, “pygmy” or “dwarf,” through Latin pygmaeus, referring to the species’ diminutive size. Amorphophallus pygmaeus is a small limestone-associated species of Thailand, with a spathe sometimes only 1.5 cm long.

NOTES:

1. Diagnosis: it differs from Amorphophallus parvulus in a shorter appendix and hemispheric stigmas, and from Amorphophallus brevispathus in generally smaller dimensions and a spadix only slightly longer than the spathe.²

2. Amorphophallus pygmaeus resembles Amorphophallus parvulus, but its appendix is shorter and thicker and the stigmas are often hemispheric. Set against Amorphophallus brevispathus it has much smaller leaves, a smaller spadix, and a connective that does not rupture at anthesis.²

3. The appendix gives off a heavy gaseous smell at female anthesis - a large gesture from a plant whose whole spadix is only 5 to 8 cm long.²

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus pygmaeus Hett.

2. Blumea 39: 271 (1994) — protologue.

3. Alan Galloway — Amorphophallus pygmaeus, alangallowaybotanicals.com.

4. Aroideana 19 (1996):P7 - 131

5. Propagation of Amorphophallus by Leaf Petiole Cuttings — Juniper Level Botanic Garden