AMORPHOPHALLUS GIGAS

PROTOLOGUE:Amorphophallus gigas Teijsm. & Binn., published in Natuurkundig tijdschrift voor Nederlandsch Indië 24: 329 (1862). The protologue is reproduced below.

SYNONYMS:

HOMOTYPIC SYNONYMS: Conophallus gigas (Teijsm. & Binn.) Miq. in Ann. Mus. Bot. Lugduno-Batavi 1: 285 (1864)

HETEROTYPIC SYNONYMS: Amorphophallus brooksii Alderw. in Bull. Jard. Bot. Buitenzorg, sér. 3, 1: 268 (1920)

DISTRIBUTION: Sumatera: Sumatra.

SPECIES DESCRIPTION:

Tuber depressed-globose, reported to weigh to 70 kg, no annual offsets. Leaf solitary; petiole ca. 3–4 m long, ca. 11–20 cm in diam., smooth or rugose near the base, dark green with numerous large and small, rounded or elongate-oval, pale green spots; lamina to 4 m in diam.; leaflets lanceolate, long acuminate, 13–25 cm long, 5–9 cm in diam.

INFLORESCENCE:

Inflorescence long-peduncled, reported to reach to 4.36 m high; peduncle ca. 2–3.5 m long, patterned as petiole; spathe campanulate, erect, broadly ovate, ca. 55–60 cm long, outside dark green changing to pale green, the margin dark red-brown, the base dark olive-green with some obscure ringlike, paler spots, inside pale green with reddish brown spots and reddish veins, margin plicate-sinuous, veins in all parts strongly raised. Spadix longer than spathe, sessile, ca. 150 cm long, emitting a foul stench of decaying meat (the Dutch protologue described it as an unbearable smell of rotting fish) upon flowering.

ECOLOGY:

Found in shady understories

PROPAGATION:

Cuttings taken in November rooted from a low of 0% to a high of 62.5% when taken in early August.

ETYMOLOGY:

From Greek gigas, “giant,” referring to the immense stature of the species, which produces one of the tallest inflorescences in the genus.

NOTES:

1. Amorphophallus gigas ranks as the second bulkiest species in the genus, and certainly the tallest one in flower! It is in most respects very similar to the Javan Amorphophallus decus-silvae (see descr.). Excellent historical photos are seen in Aroideana 4(2): 43, 44, albeit under its synonym Amorphophallus brooksii.

2. Grow in a loose, well-drained but fertile soil. The tuber must not be exposed when dormant. Many growers in the USA did receive seeds of this species from an expedition by the first author together with the late Dr. James Symon. Although many seem to have germinated, an equal number of plants seem to have perished in many places in their second or third year. This may have been caused by using too heavy a soil.

3. Though interesting for its time, the protologue describes an experiment of suspending a thermometer inside the flower, but it failed to register a change in temperature from the surrounding air (tested morning and evening for six days).

4. The experiment above also had two additional interesting findings: they noted that shortly after anthesis, the appendix was covered with liquid, as though coated with heavy dew. The liquid has the same unpleasant smell of rotting fish. They also noted that despite no thermogenesis being observed, pollen was discharged the third day after anthesis, but did not lead to succesfull pollination (assuming no thermogenesis might have not helped bring pollinators in)

5. Phenology of Amorphophallus gigas

According to observations made since February 25th, which were found in a state of bud to wither on March 14th, 2020, the flowering phase of the “bunga bangkai” was 19 days. The life cycle of Amorphophallus titanum consists of several phases, namely the leafy phase (vegetative phase) and the flowering phase (generative phase). Between the two phases, the sleep phase (dormancy phase) is punctuated. The “bunga bangkai” is a compound interest with a spadix type of flower. Solitary inflorescence with short inflorescences. On the end of the cob has a cone (appendix) which is a sterile part

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus gigas Teijsm. & Binn.

2. Natuurkundig tijdschrift voor Nederlandsch Indië 24: 329 (1862) — protologue.

3. Phenology of the bunga bankai (Amorphophallus gigas) in North Padang Lawas, North Sumatra, Indonedia

4. Alan Galloway — Amorphophallus gigas, alangallowaybotanicals.com.

5. Aroideana 19 (1996):P7 - 131

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