Common Name:

General Information

Arisaema tortuosum is a herbaceous perennial plant growing from a tuber that is usually renewed seasonally. The plant produces 2 - 3 leaves (occasionally only one) 5 - 30cm or more tall with a flowering stem 30 - 50cm tall - occasionally the plant can be as much as 2 metres tall. The tuber also produces some tubercles around its base - these become separated from the old tuber at the end of the season, growing on in subsequent years to form new plants[].
The plant is sometimes harvesed from the wild for local use as a food, medicine and as a source of a pesticide. It is grown as an ornamental in gardens.

Known Hazards

The plant contains calcium oxylate crystals. These cause an extremely unpleasant sensation similar to needles being stuck into the mouth and tongue if they are eaten but they are easily neutralized by thoroughly drying or cooking the plant or by steeping it in water.

Botanical References

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Range

E. Asia - southern central China, Pakistan, India, Sri Lanka, Nepal, Myanmar

Habitat

Moist shady places in forests, shrubberies and also on open slopes; at elevations of 1,500 - 3,000 metres[, ]. Rocky slopes, path sides, streamsides, especially in disturbed areas; at elevations from 1,300 - 2,900 metres[].

Properties

Edibility Rating
Medicinal Rating
Habit	Perennial
Height	0.40 m
Pollinators	Flies
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

Arisaema tortuosum is only hardy outdoors in he milder regions of the temperate zone - it can tolerate occasional temperatures as low as about -10°c, especially if the tubers are planted about 20cm deep[].
Prefers a cool peaty soil in the bog garden, woodland garden or a sheltered border in semi-shade[, ]. Prefers a loamy or peaty soil and will tolerate a sunny position if the soil is moist but not water-logged and the position is not too hot or exposed[, ].
Plants require protection from slugs[].
Most species in this genus are dioecious, but they are sometimes monoecious and can also change sex from year to year. This species usually bears either monoecious or all male flowers[].
The plant is paradioecious. The sex depends on nutrition and is therefore variable from one year to another[]. Smaller plants produce only staminate flowers, whilst larger plants produce either staminate and pistillate flowers simultaneously or pistillate flowers only. Changes in gender expression are directly correlated with size and are also influenced by the environment in which the plants are growing. Reversions in phenotypic gender have been experimentally induced by such factors as removing leaf area or changing soil nutrient levels[].

Edible Uses

Tuber - it must be thoroughly dried or cooked before being eaten[, ]. The tubers are boiled and eaten in Nepal, mixed with lime juice (Citrus aurantifolia) or another sour substance[]. The tubers are 2 - 6cm in diameter[].
The tubers are buried in masses in pits until acetous fermentation takes place, they are then dug up, washed and cooked, by which means their acrimonious principles are in part dispersed[]. However, violent illness has still been known to follow a hearty meal of the tubers[]. See also the notes above on toxicity.

Medicinal

The roots have been used as a vermifuge in cattle[, ]. The juice of the tubers is applied to the wounds of cattle in order to kill any parasites[]. The dried powdered tubers is applied to snake bites[].

The seeds have been mixed with salt and used to treat colic in sheep[, , ].

Other Uses

The tubers have insecicidal properties[].

Propagation

Seed - best sown as soon as it is ripe in a shady position in a cold frame[]. Stored seed remains viable for at least a year and can be sown in spring in the greenhouse but it will probably require a period of cold stratification. Germination usually takes place in 1 - 6 months at 15°c[]. When large enough to handle, prick the seedlings out into individual pots and grow them on in light shade in the greenhouse for at least a coupe of years until the corms are more than 20mm in diameter. Plant out into their permanent positions whilst they are dormant.
Division of tubers when the plant dies down in late summer.