Biology:Hesperocyparis arizonica

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Short description: Species of conifer

Hesperocyparis arizonica
Hesperocyparis arizonica - Cricket Raspet 01.jpg
Hesperocyparis arizonica (Arizona cypress) foliage and cone
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnospermae
Division: Pinophyta
Class: Pinopsida
Order: Cupressales
Family: Cupressaceae
Genus: Hesperocyparis
Species:
H. arizonica
Binomial name
Hesperocyparis arizonica
(Greene) Bartel
Cupressus arizonica range map 1.png
Natural range of Hesperocyparis arizonica
Synonyms[2]

Hesperocyparis arizonica, the Arizona cypress, is a North American species of tree in the cypress family Cupressaceae, native to the southwestern United States and Mexico. Populations may be scattered rather than in large, dense stands.

Description

Hesperocyparis arizonica tree in Chiricahua National Monument, Arizona

Hesperocyparis arizonica is a coniferous evergreen tree with a conic to ovoid-conic crown. It grows to heights of 10–25 m (33–82 ft), and its trunk diameter reaches 55 cm (22 in). The foliage grows in dense sprays, varying from dull gray-green to bright glaucous blue-green. The leaves are scale-like, 2–5 mm long, and produced on rounded (not flattened) shoots. The seed cones are globose to oblong, 15–33 mm long, with 6 or 8 (rarely 4 or 10) scales, green at first, maturing gray or gray-brown about 20–24 months after pollination. The cones remain closed for many years, only opening after the bearing branch is killed (in a wildfire or otherwise), allowing the seeds to colonize the bare ground exposed by the fire. The male cones are 3–5 mm long, and release pollen in February–March.[3]

Taxonomy

Hesperocyparis arizonica was given its first scientific name and described by Edward Lee Greene in 1882 as Cupressus arizonica, placing it in genus Cupressus.[2][4] This description was soon after disputed by Maxwell T. Masters who, in 1896, published a journal article where he said it should be considered a subspecies of Cupressus benthamii with the variety name of arizonica.[2] A similar classification reducing it to a subspecies as Cupressus lusitanica subsp. arizonica was posthumously published by René Maire in 1952.[2] There also have been publications that suggested moving it as a species to a different genus such as Callitropsis in 2006 and a new genus, Neocupressus, in 2009.[2]

As of 2024 Plants of the World Online (POWO) and World Flora Online (WFO) now list H. arizonica as the correct species name, crediting Jim A. Bartel, a classification also published in 2009.[2][5] However a few botanists such as Didier Maerki vigorously disagree with this new classification.[6]

Other disagreements have been over the validity of various subspecies of H. arizonica. A total of eleven have been validly published. However seven of these are listed as synonyms by POWO and WFO as of 2024.[2][5] The remaining four are listed as separate species:

Distribution

Hesperocyparis arizonica is found mainly in northern Mexico in the states of Chihuahua, Coahuila, Durango, Tamaulipas, and Zacatecas. It is also found in small areas of the southwestern United States in the southern parts of Arizona, New Mexico, and Texas . In the US it is found between 1000 and 1500 meters in elevation while in Mexico it reaches as high as 2200 meters in some forests.[11][2] In the wild, the species is often found in small, scattered populations, not necessarily in large forests. An example occurrence is within the Sierra Juárez and San Pedro Mártir pine–oak forests of Mexico,[12] where it is found along with canyon live oak and California fan palm.

Uses

Arizona cypress is widely cultivated as an ornamental tree. Unlike Monterey cypress, it has proved highly resistant to cypress canker, caused by the fungus Seiridium cardinale, and growth is reliable where this disease is prevalent.

The cultivar 'Pyramidalis'[13] has gained the Royal Horticultural Society's Award of Garden Merit (confirmed 2017).[14]

Example of neoendemism and conservation challenges

The ease of hybridization of western cypress species in the American southwest has fostered a parallel history of taxonomic disagreements of where genus and species distinctions should apply. [15] It thus provides a case study of neoendemism in conifers. Close taxonomic relatedness, in turn, offers both challenges and opportunities if and when assisted migration is considered as a mode of climate adaptation to prevent extinctions of endemic cypresses in the American southwest.[16]

References

  1. ↑ Farjon, A. (2013). "Cupressus arizonica". IUCN Red List of Threatened Species 2013: e.T42216A2962318. doi:10.2305/IUCN.UK.2013-1.RLTS.T42216A2962318.en. https://www.iucnredlist.org/species/42216/2962318. Retrieved 12 November 2021. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 "Hesperocyparis arizonica (Greene) Bartel" (in en). Royal Botanic Gardens, Kew. http://www.plantsoftheworldonline.org/taxon/60451546-2. 
  3. ↑ Eckenwalder, James E. (1993), "Cupressus arizonica", in Flora of North America Editorial Committee, Flora of North America North of Mexico (FNA), 2, New York and Oxford, http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200005413 
  4. ↑ Greene, Edward Lee (May 1882). "New Western Plants". Bulletin of the Torrey Botanical Club (New York: Torrey Botanical Club) 9 (5): 64-65. https://www.biodiversitylibrary.org/page/648344. Retrieved 27 January 2024. 
  5. ↑ 5.0 5.1 Template:Cite WFO
  6. ↑ Mаеrki, Didier (31 January 2017). "Editorial: Recent developments in the taxonomy of the genus Cupressus and consequences for their conservation". Bulletin of the Cupressus Conservation Project 6 (1): 3–24. http://cupressus.net/bulletin/13/BullCCP06_1.pdf. Retrieved 30 January 2024. 
  7. ↑ "Hesperocyparis glabra (Sudw.) Bartel" (in en). Royal Botanic Gardens, Kew. http://www.plantsoftheworldonline.org/taxon/60451551-2. 
  8. ↑ "Hesperocyparis montana (Wiggins) Bartel" (in en). Royal Botanic Gardens, Kew. http://www.plantsoftheworldonline.org/taxon/60451559-2. 
  9. ↑ "Hesperocyparis nevadensis (Abrams) Bartel" (in en). Royal Botanic Gardens, Kew. http://www.plantsoftheworldonline.org/taxon/60451560-2. 
  10. ↑ "Hesperocyparis stephensonii (C.B.Wolf) Bartel" (in en). Royal Botanic Gardens, Kew. http://www.plantsoftheworldonline.org/taxon/60451562-2. 
  11. ↑ Earle, Christopher J. (3 March 2023). "Cupressus arizonica (Arizona cypress) description" (in en). https://www.conifers.org/cu/Cupressus_arizonica.php. 
  12. ↑ National Geographic 2001.
  13. ↑ "RHS Plant Selector – Cupressus arizonica 'Blue Ice'". https://www.rhs.org.uk/Plants/85769/Cupressus-arizonica-Pyramidalis/Details. 
  14. ↑ "AGM Plants – Ornamental". Royal Horticultural Society. July 2017. p. 26. https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-ornamentals.pdf. 
  15. ↑ Rehfeldt, Gerald E (1997). "Quantitative analyses of the genetic structure of closely related conifers with disparate distributions and demographics: the Cupressus arizonica (Cupressaceae) complex". American Journal of Botany 84 (2): 190—200. https://bsapubs.onlinelibrary.wiley.com/doi/pdf/10.2307/2446080. 
  16. ↑ Barlow, Connie. "Climate, Trees, and Legacy: 04 - Lessons of Arizona Cypress". ghostsofevolution. https://youtube.com/vW_Zaowal8k. 

Further reading

External links

Wikidata ☰ Q50843037 entry



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