Sorbus is treated here in the broad sense, including the subgenera Aria and Torminaria. However, these two subgenera are likely to be recognized at generic rank, based on flower and fruit characters, once molecular studies can consistently resolve their placement within the Pyrinae, overcoming current difficulties with interfertility, reticulate relationships, rapid radiation, and small samples[
The taxonomy of Sorbus is complicated by apomixis, polyploidy, and hybridization among sections and genera, especially in Eurasia. Sorbus hybridizes with several other genera in the tribe Maleae, including Amelanchier (×Amelasorbus Rehder); Crataegus (×Crataegosorbus Makino); Aronia (×Sorbaronia C. K. Schneider); Cotoneaster (×Sorbocotoneaster Pojarkova); Pyrus (×Sorbopyrus C. K. Schneider), and Malus (×Tormimalus Holub [= Sorbus subg. Torminaria × Malus])[
Crataegus alnifolia Siebold & Zucc.
Micromeles alnifolia (Siebold & Zucc.) Koehne
Pyrus alnifolia (Siebold & Zucc.) Franch & Sav.
Common Name: Korean Mountain Ash
Sorbus alnifolia is a deciduous tree that can grow up to 20 metres tall but is more commonly 12 - 15 metres[
The tree is harvested from the wild for local use as a food and source of materials. It is grown as an ornamental in gardens, valued especially for its autumn colour and its fruits, which attract birds to the garden[
Although no specific information has been seen, the seed, and other parts of the plant, is 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[
E. Asia - Russian Far East, China, Japan, Korea.
Slopes of shady mountain forests of stone pine and deciduous trees on stony and humus rich soils[
]. Slopes, gullies, mixed forests and shrubby thickets; at elevations from 500 - 2,400 metres[
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Sorbus alnifolia is a moderately cold-hardy tree, tolerating temperatures down to around -20°c when dormant[
Succeeds in most reasonably good soils in an open sunny position[
]. Dislikes dry soils[
]. Tolerates light shade[
], though it fruits better in a sunny position[
Plants are susceptible to fireblight[
Fruit - raw or cooked[
]. The red, oblong, ovoid-oblong, or globose fruit is about the size of a pea, up to 10 - 14mm long and 7 - 10mm wide[
]; it is produced in fairly large bunches making it easy to harvest[
]. The flavour is reasonably mild and somewhat mealy[
Wood - even grained. Used for rulers[
We have no further specific information, but the wood of Sorbus species in general is hard, heavy, and fine-grained, and is suitable for making furniture or small, carved articles[
Seed - best sown as soon as it is ripe in a cold frame[
]. If you have sufficient seed it can be sown in an outdoor seedbed[
]. Stored seed germinates better if given 2 weeks warm then 14 - 16 weeks cold stratification[
], so sow it as early in the year as possible. Prick out the seedlings into individual pots when they are large enough to handle. Seedlings are very slow to put on top-growth for their first year or two[
], but they are busy building up a good root system. It is best to keep them in pots in a cold frame for their first winter and then plant them out into their permanent positions in late spring.