Rhamnus purshiana DC.

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Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Rhamnus purshiana' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhamnus/rhamnus-purshiana/). Accessed 2020-10-27.

Genus

Synonyms

  • Frangula purshiana (DC.) Cooper

Glossary

apex
(pl. apices) Tip. apical At the apex.
entire
With an unbroken margin.

References

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Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Rhamnus purshiana' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/rhamnus/rhamnus-purshiana/). Accessed 2020-10-27.

A deciduous tree up to 40 or 50 ft high in the wild; young shoots conspicuously downy. Leaves oblong or oval, rounded at the base, with a short, bluntish apex, either minutely toothed or entire, 2 to 5 in. long, 1 to 3 in. wide, downy beneath and on the veins above, veins parallel, in ten to fifteen pairs; stalk 12 to 34 in. long, downy. Flowers in stalked umbels, opening in July; sepals and petals five, flower-stalks downy. Fruits top-shaped, 13 in. long, black, usually three-seeded.

Native of western N. America; introduced in 1891. A handsome small tree, although without any beauty of blossom, forming a broad leafy head of erect or spreading branches. It is allied to R. frangula, but has more numerous parallel veins in each leaf that are downy above, and differs in the distinctly stalked flower-clusters, the common-stalk being often 12 in. or more long. R. purshiana is the source of the well-known drug, cascara sagrada, one of the most popular of aperient medicines. It is obtained from the bark, and so great was the demand that £20,000 worth was sent from the states of Oregon and Washington in 1907. The consequence is that natural supplies are being rapidly used up, and it has been suggested that the cultivation of this tree in the southern and western parts of the British Isles might prove profitable. The bark of trees raised and grown at Kew has been proved to possess the aperient quality as fully as that of wild trees.


R caroliniana Walt.

Synonyms
Frangula caroliniana (Walt.) A. Gray

This is nearly related to R. purshiana, and may be regarded as its E. American representative. It differs from the above in having narrower, more pointed leaves, with fewer (eight to ten) pairs of parallel veins. It resembles it in having stalked umbels, but the stalks are much shorter. Introduced in 1819, according to Loudon, but now rarely seen, and perhaps not very hardy. It varies from a shrub to a tree 30 to 40 ft high. Fruits red, becoming black, {1/3} in. wide, sweet.

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