AMORPHOPHALLUS THAIENSIS
PROTOLOGUE: Amorphophallus thaiensis (S.Y.Hu) Hett., published in Flora of Thailand 11(2): 178 (2012).
Amorphophallus thaiensis (S.Y. Hu) Hett. comb. nov. - Thomsonia thaiensis S.Y. Hu, Dansk Bot. Ark. 23(4): 442, Pl. 6 (Figs. 18-25). 1968. Type: T. Sørensen, K. Larsen & B. Hansen 4240 (holotype C, spirit coll.), Thailand, Chiang Mai, Doi Chiang Dao.
SYNONYMS:
HOMOTYPIC SYNONYMS: Thomsonia thaiensis S.Y.Hu in Dansk Bot. Ark. 24: 442 (1968)
DISTRIBUTION: N. Thailand: Thailand.
DISTRIBUTION NOTE: Thailand: the north, in Mae Hong Son and Chiang Mai provinces. It is endemic to Thailand.².
SPECIES DESCRIPTION:
Tuber subglobose, 2-9 by 2-7 cm high, with several large elongate-fusiform offsets about 3.5 cm long. Leaf solitary; petiole 44-60 by 0.8-1 cm, smooth, olive-brown with indistinct slightly paler shades and scattered dirty pale grey, elongate-elliptic or somewhat irregular spots. Leaf blade with relatively few leaflets, 44-60 cm across, the rachises narrowly winged beyond the main branchings; leaflets elongate-elliptic, shortly acuminate, 3-18 by 2-8 cm, the upper surface dark green and somewhat glossy.²
INFLORESCENCE:
Inflorescence long-peduncled; peduncle 11-40 by 0.7-1.5 cm, smooth, reddish brown with scattered circular or rhombic, dirty whitish or pale reddish brown spots. Spathe boat-shaped, 6.5-22 by 5-15 cm, elliptic and strongly concave, the base shortly convolute and the top acute; outside dirty greenish, with or without a strong brownish purplish flush at the base or more widely - especially in immature spathes - the upper part sometimes dark green, and with several scattered or crowded, distinct or indistinct, small or large, partly confluent dirty whitish or pale green spots in the lower part or all over; inside pale green with a faint purplish hue near the base and narrowly purplish lower margins. Spadix stalked, shorter than the spathe, 4.8-10 cm long excluding the stalk, the stalk 7-10 mm long. Female zone cylindrical, 0.3-1.5 by 1.3-1.5 cm, the flowers congested; ovaries obliquely depressed, 2-4 by 1-2 mm, bright pale green or maroon, one-chambered; style 2-3 by about 0.8 mm, straight or curved towards the spadix, bright pale green or maroon; stigma strongly depressed, 1-2 by about 0.3 mm, two-lipped with an elongate central depression, the lower margin entire or with one notch and the upper margin usually strongly wavy or notched, the surface minutely warted, dirty pale yellowish. Male zone cylindrical, 1.5-2.5 by 1-1.5 cm, slightly flattened at the top, the flowers congested; male flowers of 4-5 stamens; stamens about 3 mm long; filaments connate only at the base, 2 mm long, white; anthers 1 by 1-2 mm, white, the connective broad and often slightly depressed, the pores slit-like and marginal, connecting to the sides by a groove. Appendix ovoid to shortly conical, 2-6.5 by 1-4 cm, not or slightly flattened, with or without one or two broad lengthwise depressions, the top broadly obtuse, the surface smooth, dirty white with or without a pale purple flush. Infructescence 12 by 5 cm, the berries slightly apart; fruits elongate, 10-15 by 5-8 mm, ripening to a glossy bright blue.²
PROPAGATION:
In 14 attempts, we have achieved results from 100% in early August to 0% in the same time frame. Early September cuttings range from 8.7% to 52.3%, and plants with new growth rooted 81.3% from early November cuttings. Two of the species which produced tubers the fastest (around 6 weeks) were Amorphophallus bulbifer and Amorphophallus thaiensis.
ETYMOLOGY:
From Thailand, where the type was gathered on Doi Chiang Dao in Chiang Mai and where the species is confined. Shirley Hu published it in 1968 as Thomsonia thaiensis, and it was moved into Amorphophallus in the Flora of Thailand.²
NOTES:
1. The species was first described in the genus Thomsonia, which is no longer kept separate; the combination in Amorphophallus was made in the Flora of Thailand.²
2. The ripe fruits are a glossy bright blue - an uncommon colour in the genus, where red and orange are the rule.²
3. The stigma is two-lipped, with the upper margin strongly wavy or notched and the lower one entire or with a single notch.²
4. The spadix is stalked, and shorter than the spathe.²
5. Nothing has been recorded of its ecology.²
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus thaiensis (S.Y.Hu) Hett.
2. Flora of Thailand 11(2): 178 (2012) — protologue.
3. Alan Galloway — Amorphophallus thaiensis, alangallowaybotanicals.com.
4. Propagation of Amorphophallus by Leaf Petiole Cuttings — Juniper Level Botanic Garden