The taxonomy of the genus Malus is very confused - it has been revised on several occasions, with some authors placing species within the genus Pyrus. Recent morphologic work has suggested that Malus be retained as a separate genus based on fully adnate carpels and deeply inferior ovaries, with molecular evidence providing support. However, cultivation, hybridization, and introgression have led to hundreds of species being named within Malus and there is no clear agreement as to the number of accepted distinct species, or indeed the appropriate name for many of them. The genus requires a comprehensive worldwide revision[].

Common Name: Japanese Crab Apple

General Information

Malus toringo is a deciduous shrub or more commonly a small tree usually growing 2 - 8 metres tall, occasionally reaching 10 metres. The bole can be 30cm in diameter[].
The tree is harvested from the wild for local use as a food. The fruit is sometimes sold in local markets in Korea for use in making wine[]. The plant is sometimes used as a rootstock and in breeding programmes to improve the apple, and is also occasionally cultivated as an ornamental.
There are several known threats to the forests of China, particularly illegal logging and legal deforestation as a result of increasing population pressures and urbanization; air and water pollution are also having a detrimental effect on China's forests. The impact of these habitat threats on Malus toringo remains unknown, and further threats to this species also remain unknown.The plant is classified as 'Data Deficient' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

Although no specific information has been seen, the seed and other parts of the plant (but not the fruit) are likely to contain cyanogenic glycosides. When injested, these compounds break down in the digestive tract to release cyanide. Used in small quantities in both traditional and conventional medicine, this exceedingly poisonous compound has been shown to stimulate respiration, improve digestion, and promote a sense of well-being[]. It is also claimed by some to be of benefit in the treatment of cancer - though this claim has been largely refuted.
In larger concentrations, however, cyanide can cause gasping, weakness, excitement, pupil dilation, spasms, convulsions, coma and respiratory failure leading to death[].
The levels of toxin can be detected by the level of bitterness:- sweet almonds, for example, contain only very low levels of it and are safe to eat in quantity, whilst bitter almonds (which are used as a flavouring in foods such as marzipan) contain much higher levels and should only be eaten in very small quantities. Great caution should be employed if the taste is moderately to very bitter[].

Botanical References

, ,

Range

E. Asia - China, Japan, Korea.

Habitat

Mountains[]. Mixed forests amongst shrubs and on slopes; at elevations from 150 - 2,000 metres[].

Properties

Conservation Status	Data Deficient
Edibility Rating
Other Uses Rating
Habit	Deciduous Tree
Height	4.00 m
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

An easily grown plant, it succeeds in most fertile soils, preferring a moisture retentive well-drained loamy soil[, ]. Grows well in heavy clay soils. Prefers a sunny position but succeeds in partial shade though it fruits less well in such a situation[].
This species is closely related to Malus floribunda[].
Cross-compatibility amongst the different species of Malus is common. Hybridization can occur naturally in botanical gardens and in the wild, or artificially through breeding[, ].
Polyploid forms and asexual seed production (apomixis) occur in some species[].
The fruit is a good wildlife food source, especially for birds[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

Fruit - raw or cooked. It is best after a frost, the cold helping to produce more sugars in the fruit[, ]. The red or brownish-yellow, subglobose fruit is 6 - 10mm in diameter[].

Medicinal

None known

Other Uses

Seedlings have low vigour and show resistance to drought and powdery mildew. Therefore this species could be used in breeding programmes to confer disease resistance and drought resistance to the apple[].

The plant is used as a graft stock for the Apple (Malus domestica) in the Chinese provinces of Liaoning and Shandong. However, there are reports that there is a high level of graft incompatibility with the common apple[].

We do not have a specific description for the wood of this species - the following is a general description for the wood of this genus:-
The heartwood is reddish-grey; the 12 - 30 rings of sapwood are a light reddish. When steamed, the wood becomes reddish brown to dark red-brown. The wood is hard, but has a tendency to warp. It is very difficult to splitd and is difficult to work, but is easily stained and polished. The timber converts cleanly but is moderately hard to saw. A clean finish is produced normally, but a reduction of the cutting angle to 20° is an advantage to planing. The wood is generally of too small a size for commercial exploitation but, where larger sizes are attained the wood has been used for making a wide range of items, including furniture, mallet heads, umbrella handles, cog wheels, pianos, tools etc, and also for turnery[, , ].
The wood of Malus species generally makes a good fuel[, ].

Propagation

Seed - best sown as soon as it is ripe in the autumn in a cold frame. It usually germinates in late winter. Stored seed requires stratification for 3 months at 1°c and should be sown in a cold frame as soon as it is received[]. It might not germinate for 12 months or more. Prick out the seedlings into individual pots as soon as they are large enough to handle. If given a rich compost they usually grow away quickly and can be large enough to plant out in late summer, though consider giving them some protection from the cold in their first winter. Otherwise, keep them in pots in a cold frame and plant them out in late spring of the following year.
Cuttings of mature wood, late autumn in a frame[].