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: Sikkim Crab Apple

General Information

Malus sikkimensis is a deciduous tree, branching from low-down with a round-headed canopy; it can grow 6 - 8 metres tall[, , ].
The tree is harvested from the wild for local use as a food and source of materials. It is used in breeding programmes for the cultivated apple, and is also used as a rootstock for that plant. It is grown as an ornamental in gardens.
The Flora of China states that the small and isolated populations of Malus sikkimensis in China are threatened by forest clearing. Furthermore, there are several known threats to the forests of China in general, 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 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 - Himalayas of northeast India, Nepal, Bhutan, southwest China

Habitat

Open forests on slopes, mixed forests in valleys; at elevations from 2,500 - 3,000 metres[].

Properties

Conservation Status	Data Deficient
Edibility Rating
Other Uses Rating
Habit	Deciduous Tree
Height	7.00 m
Pollinators	Insects, Apomixis
Self-fertile	Yes
Cultivation Status	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. Succeeds in acid soils[]. Prefers a sunny position but succeeds in partial shade, though it fruits less well in such a situation[].
This spceies is closely related to Malus baccata[].
The fruit, which is freely produced in Britain[], is a good wildlife food source, especially for birds[].
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[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

Fruit - raw or cooked[, ]. The dark red, obovoid to pear-shaped fruit is 10 - 18mm in diameter[].

Medicinal

None known

Other Uses

This species is a secondary genetic relative and a graft stock relative of the cultivated Apple (Malus domestica) and so has potential for use as a gene donor for crop improvement; it is thought to have the potential to confer disease resistance and dwarfing traits to apple[].

Cultivated in western China and northern India as a highly compatible rootstock for apples grown on acid soils. An apomictic species, it gives uniform and virus-free progenies[].

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[].