Purshia
Credits
Article from Bean's Trees and Shrubs Hardy in the British Isles
Recommended citation
'Purshia' from the website Trees and Shrubs Online (treesandshrubsonline.
Family
- Rosaceae
Common Names
- Bitterbrush
- Cliff Rose
Synonyms
Editorial Note
Bean treated species in this genus under both Purshia, and Cowania, now regarded as synonymous on the basis of molecular data and vegetative and floral – but not fruit – morphology (see below). Brief text is supplied here, pending a full, revised treatment of the expanded genus, to be provided when funding allows. If you would like to sponsor the account please write to editor@treesandshrubsonline.org
Multi-stemmed shrubs with leathery leaves densely hairy beneath. Flowers solitary; sepals 5; petals 5, caducous, white, cream or yellow; stamens many, shorter than petals; carpels 1–31; fruit an achene with a persistent style. Flora of North America, 2025.
Six or seven species, evergreen or drought-deciduous or with other xeric adaptations. The range of the genus extends from northern Mexico and the western United States (east to Nebraska) to Western Canada. The modern concept of Purshia comprises Cowania (3–31 carpels with remarkable plumose styles persisting on the wind-dispersed fruits) and Purshia s.s. (1–3 carpels, the persistent styles short, curved). There is a high degree of variability at species level, with widespread hybridisation and introgression between the various taxa documented. Associated with the symbiotic nitrogen-fixing bacterium Frankia, which induces the formation of root-nodules. The genus is named after F. Pursh, a botanist of German birth who is the author of Flora americae septentrionalis (1814), one of the first works on the flora of North America. Flora of North America, 2025; Bean 1976a