Prunus murrayana was long known only from trans-Pecos Texas. M. F. Enquist (1997) expanded the range by recognizing the similarity of these plants to plants from the Edwards Plateau, which he described as a hairy variety of Prunus rivularis and placed Prunus murrayana in synonymy. Sequence analysis of DNA from some of the same hairy plants collected by Enquist indicate that these plants are distinct from Prunus rivularis and are most similar to Prunus hortulana. Although closely related, Prunus murrayana differs from Prunus hortulana in being smaller, with smaller leaves and fruits; it also suckers to form shrubby thickets; whilst Prunus hortulana generally forms single trees; in addition, the twigs, pedicels, and hypanthium exteriors are hairy in Prunus murrayana and glabrous in Prunus hortulana[
The taxonomic history of Prunus is long and complicated, in part due to the economic value of its fruit crops and also the ease with which some species hybridize. Here, Prunus is circumscribed in its broad sense based on the argument that when viewed on a worldwide scale, the morphologic discontinuities among the segregate genera diminish and they overlap with one another. Included here are species that have at times been placed in the genera Amygdalus, Armeniaca, Cerasus, Laurocerasus, Padus, and Persica.
At the species level, Prunus has been the object of the usual combining and splitting common among taxonomists with different philosophies and opinions. In particular, over-reliance on the indument of various vegetative and floral parts has led to the naming of numerous species and infraspecific taxa. Similarly, too much has been made of fruit colour and palatability in naming taxa of Prunus. It is very likely that, as molecular and genetic data are analyzed and, more importantly, correlated with morphological data, circumscriptions will be redrawn and the number of Prunus species will be reduced[
Prunus rivularis pubescens Enquist
Prunus murrayana is a more or less thorny, deciduous shrub, intricately branched or sometimes growing with erect stems and few ascending branches; it usually grows 50 - 300cm tall, occasionally reaching 500cm. The plant usually suckers, forming shrubby thickets[
The plant has potential use in breeding programmes for the Japanese Plum and Cherry Plum. The fruit is possibly edible.
Fruits have not been observed in the population so it is suspected that this species is not reproducing - as a result, no plants can be recorded as mature individuals unless new evidence can be put forward to show the remaining plants are able to reproduce. Additionally, continuing decline of the population is inferred from its inability to reproduce. Furthermore, the species has no known conservation in place, this is a concern as with no human intervention it's long-term survival is highly unlikely. The plant is classified as 'Critically Endangered' in the IUCN Red List of Threatened Species(2013)[
]. It is possible that the above report is based on a narrow view of the species and that, when Prunus rivularis pubescens is recognized as a synonym (see notes above on taxonomy) the population of Prunus murrayana is somewhat larger[
The plant (especially the seed and young shoots) contains cyanogenic glycosides, especially amygdalin and prunasin. 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 fruits and flowers of most members of this genus generally have low or very low concentrations of this toxin, though the seeds and young shoots can contain much higher levels.
The levels of toxin can be detected by the level of bitterness:- for example sweet tasting almond seeds are a major food crop and are often eaten in quantity, whilst bitter tasting almond seeds are used as a flavouring (in marzipan for example) but are not usually eaten on their own.
In general, it can be considered safe to eat any fruit or seed from species in this genus that either have a sweet flavour or are slightly bitter. Great caution should be taken, however, if the flavour is moderately to very bitter[
Southern N. America - Texas
Rocky stream banks, canyons, dry washes, fence rows; at elevations from 500 - 1,500 metres[
|Conservation Status||Critically Endangered
|Other Uses Rating||
Requires a sunny position. Thrives in a well-drained moisture-retentive loamy soil[
]. Prefers some lime in the soil but is likely to become chlorotic if too much lime is present[
]. Established plants are drought tolerant.
Most members of this genus are shallow-rooted and will produce suckers if the roots are damaged[
Plants in this genus are notably susceptible to honey fungus[
Fruit - raw or cooked. A succulent flesh[
]. The fruit is red with white dots, globose and around 10 - 18mm in diameter, containing a single, large seed[
Seed - raw or cooked. Do not eat the seed if it is too bitter - see the notes above on toxicity.
Although no specific mention has been seen for this species, all members of the genus contain amygdalin and prunasin, substances which break down in water to form hydrocyanic acid (cyanide or prussic acid). In small amounts this exceedingly poisonous compound stimulates respiration, improves digestion and gives a sense of well-being[
A green dye can be obtained from the leaves[
A dark grey to green dye can be obtained from the fruit[
Prunus murrayana belongs to the secondary Gene Pool of the Myrobalan Plum (Prunus cerasifera Ehrh.) and Japanese Plum (Prunus salicina Lindl.), and so it has the potential for use as a gene donor for crop improvement[
Seed - requires 2 - 3 months cold stratification and is best sown in a cold frame as soon as it is ripe[
]. Sow stored seed in a cold frame as early in the year as possible[
]. Protect the seed from mice etc. The seed can be rather slow, sometimes taking 18 months to germinate[
]. Prick out the seedlings into individual pots when they are large enough to handle. Grow them on in a greenhouse or cold frame for their first winter and plant them out in late spring or early summer of the following year.
Cuttings of half-ripe wood with a heel, mid summer in a frame[
Softwood cuttings from strongly growing plants in spring to early summer in a frame[
Layering in spring.