''Hesperocyparis arizonica'', the Arizona cypress, is a North American

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of tree in the cypress family Cupressaceae,

native Native may refer to: People * '' Jus sanguinis'', nationality by blood * '' Jus soli'', nationality by location of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Nat ...

to the southwestern United States and Mexico. Populations may be scattered rather than in large, dense stands.

Description

''Hesperocyparis arizonica'' is a

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

ous

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

tree with a

conic A conic section, conic or a quadratic curve is a curve obtained from a cone's surface intersecting a plane. The three types of conic section are the hyperbola, the parabola, and the ellipse; the circle is a special case of the ellipse, thou ...

to ovoid-conic crown. It grows to heights of , and its trunk diameter reaches . The foliage grows in dense sprays, varying from dull gray-green to bright

glaucous ''Glaucous'' (, ) is used to describe the pale grey or bluish-green appearance of the surfaces of some plants, as well as in the names of birds, such as the glaucous gull (''Larus hyperboreus''), glaucous-winged gull (''Larus glaucescens''), ...

blue-green. The leaves are scale-like, 2–5 mm long, and produced on rounded (not flattened) shoots. The seed

cones In geometry, a cone is a three-dimensional figure that tapers smoothly from a flat base (typically a circle) to a point not contained in the base, called the ''apex'' or '' vertex''. A cone is formed by a set of line segments, half-lines, ...

are

globose This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary ...

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 A wildfire, forest fire, or a bushfire is an unplanned and uncontrolled fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a ...

or otherwise), allowing the

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s to colonize the bare ground exposed by the fire. The male cones are 3–5 mm long, and release pollen in February–March.

Taxonomy

''Hesperocyparis arizonica'' was given its first scientific name and described by

Edward Lee Greene Edward Lee Greene (August 20, 1843–November 10, 1915) was an American botanist known for his numerous publications including the two-part ''Landmarks of Botanical History'' and the describing of over 4,400 species of plants in the American W ...

in 1882 as ''Cupressus arizonica'', placing it in genus ''

Cupressus ''Cupressus'' (common name cypress) is one of several genus, genera of evergreen conifers within the Family (biology), family Cupressaceae; for the others, see cypress. It is considered a Polyphyly, polyphyletic group. Based on genetic and morpho ...

''. 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''. A similar classification reducing it to a subspecies as ''

Cupressus lusitanica ''Hesperocyparis lusitanica'', the Mexican cypress, cedar-of-Goa or Goa cedar, is a species of Cupressaceae, cypress native to Mexico and Central America (Guatemala, El Salvador and Honduras). It has also been introduced to Belize, Costa Rica a ...

'' subsp. ''arizonica'' was posthumously published by

René Maire René Charles Joseph Ernest Maire (; 29 May 1878, Lons-le-Saunier – 24 November 1949) was a French botanist and mycologist. His major work was the ''Flore de l'Afrique du Nord'' in 16 volumes published posthumously in 1953. He collected plants ...

in 1952. 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. As of 2024

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

(POWO),

World Flora Online World Flora Online is an Internet-based compendium of the world's plant species. Description The World Flora Online (WFO) is an open-access database, launched in October 2012 as a follow-up project to The Plant List, with the aim of publishi ...

(WFO), and the USDA

Natural Resources Conservation Service Natural Resources Conservation Service (NRCS), formerly known as the Soil Conservation Service (SCS), is an agency of the United States Department of Agriculture (USDA) that provides technical assistance to farmers and other private landowners and ...

PLANTS database (PLANTS) list ''H. arizonica'' as the correct species name. This classification was published by Jim A. Bartel in 2009. However, ''Cupressus'' continues to be used in professional papers by some scientists. 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 A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

by POWO and WFO as of 2024. The remaining four are listed as separate species: * '' Hesperocyparis glabra'' formerly ''Cupressus arizonica'' var. ''glabra'' – Smooth Arizona cypress * '' Hesperocyparis montana'' formerly ''Cupressus arizonica'' var. ''montana'' – San Pedro Mártir cypress * '' Hesperocyparis nevadensis'' formerly ''Cupressus arizonica'' var. ''nevadensis'' – Paiute cypress * ''

Hesperocyparis stephensonii ''Hesperocyparis stephensonii'' is a species of western cypress known as the Cuyamaca cypress that is found only in one very small area in Southern California. Distribution The Cuyamaca Cypress only verifiably exists in the river source, headwat ...

'' formerly ''Cupressus arizonica'' var. ''stephensonii'' – Cuyamaca cypress

Distribution

''Hesperocyparis arizonica'' is found mainly in northern Mexico in the states of Chihuahua,

Coahuila Coahuila, formally Coahuila de Zaragoza, officially the Free and Sovereign State of Coahuila de Zaragoza, is one of the 31 states of Mexico. The largest city and State Capital is the city of Saltillo; the second largest is Torreón and the thi ...

Durango Durango, officially the Free and Sovereign State of Durango, is one of the 31 states which make up the Political divisions of Mexico, 32 Federal Entities of Mexico, situated in the northwest portion of the country. With a population of 1,832,650 ...

Tamaulipas Tamaulipas, officially the Free and Sovereign State of Tamaulipas, is a state in Mexico; one of the 31 states which, along with Mexico City, comprise the 32 federal entities of Mexico. It is divided into 43 municipalities. It is located in nor ...

, and

Zacatecas Zacatecas, officially the Free and Sovereign State of Zacatecas, is one of the Political divisions of Mexico, 31 states of Mexico. It is divided into Municipalities of Zacatecas, 58 municipalities and its capital city is Zacatecas City, Zacatec ...

. It is also found in small areas of the southwestern United States in the southern parts of

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

, and

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

. 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. 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, 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 ''Hesperocyparis macrocarpa'' also known as ''Cupressus macrocarpa'', or the Monterey cypress is a coniferous tree, and is one of several species of cypress trees native to California. The Monterey cypress is found naturally only on the Centr ...

, it has proved highly resistant to cypress canker, caused by the fungus ''

Seiridium ''Seiridium'' is a genus of plant pathogens in the family Sporocadaceae. The genus '' Lepteutypa'' is teleomorphic (reproducing sexually) and the corresponding anamorphic name, used to describe the asexual form, is ''Seiridium'' (formerly ''Co ...

cardinale'', and growth is reliable where this disease is prevalent. The

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

'Pyramidalis' has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

(confirmed 2017).

Example of neoendemism and conservation challenges

The ease of hybridization of western cypress species in the

American southwest The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural list of regions of the United States, region of the United States that includes Arizona and New Mexico, along with adjacen ...

has fostered a parallel history of taxonomic disagreements of where genus and species distinctions should apply. 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 Climate change adaptation is the process of adjusting to the effects of climate change, both current and anticipated.IPCC, 2022Annex II: Glossary öller, V., R. van Diemen, J.B.R. Matthews, C. Méndez, S. Semenov, J.S. Fuglestvedt, A. Reisinger ...

to prevent extinctions of endemic cypresses in the American southwest.

References

External links

USDA Plants Profile for ''Hesperocyparis arizonica'' (Arizona cypress)
* as ''Hesperocyparis stephensonii'' * as ''Hesperocyparis stephensonii''
Hike Arizona.com: Photos of Arizona Cypress (''Cupressus arizonica'')
* {{Taxonbar, from=Q50843037 arizonica Flora of Arizona Flora of New Mexico Flora of Texas Flora of Chihuahua (state) Flora of Coahuila Flora of Durango Flora of Tamaulipas Flora of Zacatecas Trees of Northern America Flora of the Sierra Madre Occidental Flora of the Sierra Madre Oriental Natural history of the Transverse Ranges Plants described in 1882 Taxa named by Edward Lee Greene Least concern flora of North America