AMORPHOPHALLUS YULOENSIS

PROTOLOGUE: Amorphophallus yuloensis H.Li, published in Journal of Wuhan Botanical Research 6: 211 (1988).

Amorphophallus yuloensis H. Li, J. Wuhan Bot. Res. 6: 211 (1988). Type: China, Yunnan, Mengla Xian, Menglun, Yuloshan, 610 m, in forest on limestone, Li Heng 1102 (KUN).

DISTRIBUTION: E. Himalaya to China (Yunnan): China South-Central, East Himalaya, Myanmar.

DISTRIBUTION NOTE: iNaturalist: Yunnan.

SPECIES DESCRIPTION:

A tuberous plant 10-75 cm high. Tuber globose or subglobose, up to 12 cm across, the apex flat or hollowed and sometimes with hollow lobes at the margin, the base round or swollen, yellow within and brown outside. Leaf solitary; petiole green or light green and only rarely darker, 10-75 cm long and 0.5-2 cm across at the base; blade light to medium green, 10-100 cm across; the rachis winged from the branching point and carrying a brown bulbil at the tip of the petiole or at the branching points - these strike and grow into new plants once they fall to the ground. Leaf lobes elliptic to oblong-elliptic, 2-25 by 2-10 cm, the apex acute to acuminate and the base attenuate.⁷

INFLORESCENCE:

Inflorescence solitary; peduncle light to dark green with short stripes or spots, about 10 cm long and 8 mm across, smooth. Spathe straight, broadly ovate, 10-12 cm long and about 10 cm wide, the margin a little convolute and the apex obtuse, opening completely at anthesis; outside light green, light pink at the middle, scattered with dark green or dull cream dots; inside light pink at the base and densely waxy. Spadix sessile, shorter than the spathe, 8-9 cm long; female portion cylindrical, 1-2 cm long and 1-1.3 cm across, the ovaries closely set; male portion lozenge-shaped, 1.5-4 cm long and about 1.5 cm across, each flower of two to four stamens together; appendix stout conical, 3-4 cm long and 1.8 cm across, smooth, the apex obtuse. Ovary flattened globose, 2-2.5 mm high and 4 mm across, green, two-chambered with a single basal ovule in each; style ivory white, short but conspicuous, nearly 1 mm long and 1 mm wide; stigma disc-shaped, dull yellow, about 2.5 mm across, hollowed at the middle. Stamens about 2 mm long; filament 0.8 mm long; anther ivory white and blunt, 1 by 2 mm, attached at the base and opening by an apical pore. Berries violet blue.⁷

ECOLOGY:

Grows in disturbed broad-leaved evergreen forest; the Vietnamese plants studied were at 800 m, the type came from limestone forest at 610 m, and the species is recorded over a range from 200 to 2400 m. It flowers in April and fruits from June to August.⁷

PROPAGATION:

In our six attempts to root this species, only our mid-November attempt failed completely. Our best results were from early November cuttings when we achieved 100% and 83.3% rooting in two separate attempts.

ETYMOLOGY:

Probably derived from Yulo, a geographical name in Yunnan, and Latin-ensis, “from” or “of,” giving the sense “from Yulo.” The species was described from Yunnan, although the 1996 account does not provide an etymological explanation or sufficiently detailed type locality to establish the precise modern place meant by “Yulo.” I would therefore keep the geographical interpretation qualified unless we retrieve H. Li’s original protologue.

NOTES:

1. It belongs to a group within the genus whose peduncles are very short - shorter than the spathe. Within that group it is told by a much smaller inflorescence, a stout conical appendix and violet-blue berries.⁷

2. Violet-blue fruit is unusual in the genus, where red and orange are the rule.⁷

3. It propagates three ways at once: by offsets from the parent tuber, from seed, and from bulbils carried on the leaf rachis, which root after dropping to the ground.⁷

4. The tubers are worth something. They run to about 29 per cent glucomannan by dry weight - the polysaccharide sold as konjac powder - which puts the species among a small number in Vietnam considered worth exploiting for it.⁷

5. The 2017 account was the first description drawn from Vietnamese material; the species had been known from Yunnan since 1988.⁷

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus yuloensis H.Li

2. Journal of Wuhan Botanical Research 6: 211 (1988) — protologue.

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

4. Aroideana 19 (1996):P7 - 131

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

6. iNaturalist: Amorphophallus yuloensis

7. Biological Characteristics and Distribution of the species Amorphophallus yuloensis H. Li (Araceae) in Vietnam. Aroideana 40(1): 57-61 (2017)