AMORPHOPHALLUS KORATENSIS
PROTOLOGUE:Amorphophallus koratensis Gagnep., published in Notulae Systematicae (Paris) 9: 118 (1941). The protologue is reproduced below.
DISTRIBUTION: Indo-China: Cambodia, Laos, Thailand.
SPECIES DESCRIPTION:
Tuber depressed-globose, 10-14 cm in diam., ca. 7 cm high, dark brown, surface irregular and with large, annulate root scars, developing few offsets; offsets rhizomatous, to ca. 10 cm long, ca. 1.5 cm in diam. Leaf solitary or two on one tuber; petiole entirely pale green, or the basal part largely blackish, surface echinate-scabrate, 60-200 cm long, 1-3 cm in diam. (base); lamina 35-150 cm in diam.; leaflets broadly elliptic or obovate, shortly acuminate, 10-20 cm long, 4-10 cm in diam., margin slightly wavy, main veins on the upper side impressed.³
INFLORESCENCE:
Inflorescence solitary, shortly to moderately long-peduncled; peduncle 1.0-16 cm long, ca. 7 mm in diam., color etc. as in petiole; spathe erect, acute, slightly campanulate, ovate, 10-15 cm long, 9-10 cm in diam., for the greater part convolute, only the upper fourth part open, leaving only the larger part of the appendix visible, base very leathery, with a shallow apical constriction, margins slightly wavy, outside entirely green, or base pale yellowish with greenish spots, limb maroonish to the margin, inside entirely green, or base pale and dark maroon, middle part yellowish, limb mostly maroon, base inside densely verrucate, verrucae large, flattened or subhemisphaeric, separated by grooves. Spadix shorter than spathe, 10-12 cm, very shortly stipitate.³
ECOLOGY:
Found in rocky bamboo/deciduous forest³
PROPAGATION:
Late and early season cuttings were a total failure, but cuttings taken in early August rooted at 38.9%.
ETYMOLOGY:
From Korat, the traditional and still widely used name for Nakhon Ratchasima and the surrounding region of Thailand, together with Latin-ensis, “from” or “of.” The epithet therefore means “from Korat.” Amorphophallus koratensis occurs in the seasonally dry forests of central and northeastern mainland Southeast Asia.
NOTES:
1. Amorphophallus koratensis is most similar to Amorphophallus scaber (South Vietnam) in many respects. Both species possess a tubular spathe that hardly opens, similar tubers, offsets, floral morphology and leaf structure (echinate-scabrate petiole surface). Amorphophallus scaber however has much larger dimensions and the spathe is cymbiform and opens even less than Amorphophallus koratensis. Equally similar is Amorphophallus opertus but the latter has an undivided stigma and unilocular ovaries (vs. bilocular in Amorphophallus koratensis). This species is quite often sold in Thai markets, and the tuber cannot be distinguished from those for sale of Amorphophallus paeoniifolius unless parts of the petiole base are still on it.³
2. Translated from the protologue: "I could not liken this species to any other; among the campanulate-lobed spathes I see none with so reduced a conical appendix."²
3. Fresh pollen of Amorphophallus koratensis is short-lived: viability was highest (93.2%) on the first day after anthesis and declined sharply by the third day after anthesis. Of the storage conditions tested, cryopreservation in liquid nitrogen (-196 °C) proved the most suitable, retaining 33.8% viability after seven days of storage.⁷
4. Wilbert Hetterscheid, answering a photograph query about a plant raised from seed sold as Amorphophallus paeoniifolius (petioles green to reddish, with large white spots), suggested that the red coloration could point to Amorphophallus koratensis, which he said is often mistaken for Amorphophallus paeoniifolius when in leaf.¹¹ He later said he thought the red color was the key to the probability that the plant was Amorphophallus koratensis, adding that he had never seen red in proper Amorphophallus paeoniifolius and that Amorphophallus koratensis has more variation in color than Amorphophallus paeoniifolius.¹² The plant's identity was not settled in the exchange.
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus koratensis Gagnep.
2. Notulae Systematicae 9: 118 (1941) — protologue.
4. Propagation of Amorphophallus by Leaf Petiole Cuttings — Juniper Level Botanic Garden
5. Flora of Thailand: Amorphophallus koratensis
6. iNaturalist: Amorphophallus koratensis
8. Flora of Thailand — Araceae & Acoraceae
9. Newman et al. — New angiosperms and pteridophytes recorded for the flora of Laos
10. All Asia TCN — Cambodian Araceae specimen records
11. Aroid-L mailing list, Wilbert Hetterscheid, June 18th, 2011
12. Aroid-L mailing list, Wilbert Hetterscheid, June 23rd, 2011
Additional photos and videos by Craig Allen, Jeremiah Baer, Juan Jimenez and Oat Sutthinut