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Purshia

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Purshia
Purshia stansburyana
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Rosales
Family: Rosaceae
Subfamily: Dryadoideae
Genus: Purshia
DC. ex Poir.
Type species
Purshia tridentata
Range
Synonyms
  • Cowania D.Don ex Tilloch & Taylor
  • Greggia Engelm.
  • Kunzia Spreng.

Purshia (bitterbrush or cliff-rose) is a small genus of 5–8 species of flowering plants in the family Rosaceae which are native to western North America.

Description

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Purshia species form deciduous or evergreen shrubs, typically reaching 0.3–5 metres (1–16+12 feet) tall. The leaves are 1–3 centimetres (121+14 inches) long, deeply three- to five-lobed, with revolute margins. The flowers are 1–2 cm in diameter, with five white to pale yellow or pink petals and yellow stamens. The fruit is a cluster of dry, slender, leathery achenes which are 2–6 cm long. The roots have nodules that host nitrogen-fixing Frankia bacterium.[1]

Taxonomy

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Taxonomic history

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The genus was originally placed in the subfamily Rosoideae.[2] In the past, the evergreen species were treated separately in the genus Cowania; this genus is still accepted by some botanists.

Modern classification

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The classification of Purshia within the family Rosaceae has been unclear.[3][4] It is now placed in the subfamily Dryadoideae.[2]

Species

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Purshia comprises the following species:[5][6]

Hybrids

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The following hybrid has been described:[5]

  • Purshia × subintegra (Kearney) Henr. (P. pinkavae × P. stansburyana) – (Arizona)

Species names with uncertain taxonomic status

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The status of the following species and hybrids is unresolved:[5]

  • Purshia ciliata Dennst.
  • Purshia mollis  Lehm.
  • Purshia plicata (D.Don) Henr.
  • Purshia subintegra (Kearney) Henrickson

Distribution and habitat

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The genus is native to western North America, where the species grow in dry climates from southeast British Columbia, Canada, south throughout the western United States to northern Mexico.

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References

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  1. ^ Swensen, S.M.; Mullin, B.C. (1997). "The impact of molecular systematics on hypotheses for the evolution of root nodule symbioses and implications for expanding symbioses to new host plant genera". Plant and Soil. 194 (1–2): 185–192. doi:10.1023/A:1004240004063.
  2. ^ a b Potter, D.; Eriksson, T.; Evans, R.C.; Oh, S.; Smedmark, J.E.E.; Morgan, D.R.; Kerr, M.; Robertson, K.R.; Arsenault, M.; Dickinson, T.A.; Campbell, C.S. (2007). "Phylogeny and classification of Rosaceae". Plant Systematics and Evolution. 266 (1–2): 5–43. Bibcode:2007PSyEv.266....5P. doi:10.1007/s00606-007-0539-9.
  3. ^ Morgan, D.R.; Soltis, D.E.; Robertson, K.R. (1994). "Systematic and evolutionary implications of rbcL sequence variation in Rosaceae". American Journal of Botany. 81 (7): 890–903. doi:10.1002/j.1537-2197.1994.tb15570.x. JSTOR 2445770.
  4. ^ Eriksson, T.; Hibbs, M.S.; Yoder, A.D.; Delwiche, C.F.; Donoghue, M.J. (2003). "The phylogeny of Rosoideae (Rosaceae) based on sequences of the internal transcribed spacers (ITS) of nuclear ribosomal DNA and the trnL/F region of chloroplast DNA". International Journal of Plant Sciences. 164 (2): 197–211. doi:10.1086/346163.
  5. ^ a b c "The Plant List entry for Purshia". The Plant List, v.1.1. Royal Botanic Gardens, Kew and the Missouri Botanical Garden. September 2013. Retrieved 15 December 2020.
  6. ^ Govaerts R. "Purshia DC. ex Poir". Plants of the World Online. Board of Trustees of the Royal Botanic Gardens, Kew. Retrieved 15 December 2020.
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