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: Crab Apple

General Information

Malus sylvestris is a deciduous shrub or a tree that can grow 10 metres or more tall. The branches are more or less spiny[].
The tree is harvested from the wild for local use as a food, medicine and source of materials. It is sometimes grown as an ornamental in gardens
Although Malus sylvestris is relatively widely distributed in Europe, hybridization with the cultivated apple (Malus domestica) is thought to be having a significant impact on the population. It is not known to what extent the genetic diversity of the species has been affected.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

Europe, including Britain, from Scandanavia south and east to Spain, Greece and S.W. Asia

Habitat

Woods, scrub and hedges, especially in oak woods, on neutral to calcareous soils[, , ].

Properties

Conservation Status	Data Deficient
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	8.00 m
Pollinators	Insects
Cultivation Status	Wild

Cultivation Details

An easily grown plant, it succeeds in most fertile soils, including heavy ones, preferring a moisture retentive well-drained loamy soil[, , ]. Prefers a sunny position but succeeds in partial shade though it fruits less well in such a situation[, ].
Fairly tolerant of cutting, it succeeds in a mixed hedgerow[].
A parent of the cultivated apple[], it is often used as a rootstock[]. Modern genetic research does not support this species being anything other than a minor contributor to the development of the cultivated apple. It would appear that the apple arose almost completely from Malus sieversii - see Riccardo Velasco et al; The genome of the domesticated apple (Malus x domestica Borkh.); Nature Genetics 42, 833-839 (2010).
The fruit is a good wildlife food source, especially for birds[]. The plant has over 90 associated insect species[].
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[, ]. Used for jellies, preserves and juices[]. The flavour improves considerably if the fruit is not harvested until it has been frosted[]. The fruit is quite variable in size (it is about 2 - 4cm in diameter[]) and quality. Whilst usually harsh and acid, some forms are quite sweet and can be eaten out of hand[].
The fruit is rich in pectin and can be used in helping other fruits to set when making jam etc[, ]. Pectin is also said to protect the body against radiation[].

An edible oil can be obtained from the seed[]. It would only really be viable to use these seeds as an oil source if the fruit was being used for some purpose such as making cider and then the seeds could be extracted from the remaining pulp[].

A very pleasant tea can be made from the leaves[].

Medicinal

The fruit is astringent and laxative[, ]. The crushed fruit pulp can be used as a poultice to heal inflammations or small flesh wounds[]. The fruit is eaten to obviate constipation[].
The bark, and especially the root bark, is anthelmintic, refrigerant and soporific[, ]. An infusion is used in the treatment of intermittent, remittent and bilious fevers[, ].
The leaves contain up to 2.4% of an antibacterial substance called 'florin'[]. This inhibits the growth of a number of gram-positive and gram-negative bacteria in as low a concentration as 30 ppm[].

Other Uses

The fruit is a source of pectin[, ]. Pectin is used as a thickener in jams etc and as a culture medium in laboratories.

A red to yellow dye is obtained from the bark[].

Owing to its frost resistance, this species is of great importance for the breeding selection of cultivated forms valuable
for northern regions[].

Seedlings of Malus sylvestris are used successfully in northern regions as a rootstock for the cultivated forms of 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[, ]. An excellent 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[].