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])[
Pyrus sambucifolia Cham. & Schltdl.
Sorbus pumila Raf.
Sorbus sambucifolia is a deciduous shrub growing 100 - 300cm tall, usually from 1 - 8 erect, main stems[
The plant is harvested from the wild for local use as a food and medicine.
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[
Northwestern N. America - Alaska; E. Asia - Russian Far East, Japan.
An understroey plant in Betula ermani forests; growing with alder and Siberian stone pine in subalpine shaul thickets near the upper timberline, occasionally forming pure stands; at forest edges; separate groups; always on dry sandy or stony soils[
Sorbus sambucifolia 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[
]. Tolerates light shade[
], though it fruits better in a sunny position[
Plants can produce extremely abundant crops of fruit[
Plants are susceptible to fireblight[
There is considerable confusion over the naming of this species, trees grown under this name have included Sorbus decora., Sorbus matsumurana., Sorbus scopulina, and Sorbus sitchensis[
Fruit - raw or cooked[
]. Sweet tasting[
]. Acid, but pleasant tasting[
]. The fruit makes a good jam[
]. The red, ellipsoid fruit is 10 - 12mm × 7 - 9mm[
The fruits show some potential in early testing for treating tumors[
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.