''Cupressus stephensonii'' is a species of conifer known as the Cuyamaca cypress, and is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

Southern California Southern California (commonly shortened to SoCal) is a geographic and cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most populous urban ...

. It has been classified as ''Hesperocyparis stephensonii''. It was previously listed as ''Cupressus arizonica'' subsp. ''stephensonii'' and ''Cupressus arizonica'' var. ''glabra''.

Distribution

The Cuyamaca Cypress exists only in the

headwaters The headwaters of a river or stream is the farthest place in that river or stream from its estuary or downstream confluence with another river, as measured along the course of the river. It is also known as a river's source. Definition The ...

area of King Creek in the

Cuyamaca Mountains The Cuyamaca Mountains (Kumeyaay: ''‘Ekwiiyemak''), locally the Cuyamacas, are a mountain range of the Peninsular Ranges System, in San Diego County, southern California. The mountain range runs roughly northwest to southeast. The Laguna Mounta ...

of the

Peninsular Ranges The Peninsular Ranges (also called the Lower California province) are a group of mountain ranges that stretch from Southern California to the southern tip of the Baja California peninsula; they are part of the North American Coast Ranges, which ...

system, south of

Cuyamaca Peak Cuyamaca Peak is a mountain peak of the Cuyamaca Mountains range, in San Diego County, Southern California. Geography At , its summit is the second highest point in San Diego County. Cuyamaca Peak is located roughly from the Pacific Ocean, wi ...

within

San Diego County San Diego County (), officially the County of San Diego, is a county in the southwestern corner of the U.S. state of California. As of the 2020 census, the population was 3,298,634, making it California's second-most populous county and the f ...

in extreme

. Trees were reported growing as low as in elevation in 1998, but the presence of these individuals today has not been verified. Most individual trees occur at within the Pacific Southwest Research Station's King Creek Research Natural Area, in the

Cleveland National Forest Cleveland National Forest encompasses 460,000 acres (), mostly of chaparral, with a few riparian areas. A warm dry mediterranean climate prevails over the forest. It is the southernmost U.S. National Forest of California. It is administered by ...

Conservation

It is an

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biolo ...

Critically Endangered species, and a

California Native Plant Society The California Native Plant Society (CNPS) is a California environmental non-profit organization (501(c)3) that seeks to increase understanding of California's native flora and to preserve it for future generations. The mission of CNPS is to con ...

Inventory of Rare and Endangered Plants listed Seriously endangered species.IUCN Red List, Critically endangered species: ''Cupressus arizonica'' var. ''stephensonii'' (''Hesperocyparis stephensonii'')
. accessed 2 February 2017. The entire

native Native may refer to: People * Jus soli, citizenship by right of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Native Americans (disambiguation) In arts and entert ...

(world) population of the tree was reduced down to thirty to forty individual trees by the 2003 Cedar Fire.

Description

''Cupressus stephensonii'' may attain heights of . It usually forms a spreading tree with a central leader, only slightly taller than it is wide. The tree's female cones are about 10 mm in diameter, while cone scales are normally 6–8 mm. Often, but not always, they have conspicuous umbos 3–4 mm, which are high and conical. There are normally 100-125

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

s per cone, not at all

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''), ...

. 3-4

cotyledon A cotyledon (; ; ; , gen. (), ) is a significant part of the embryo within the seed of a plant, and is defined as "the embryonic leaf in seed-bearing plants, one or more of which are the first to appear from a germinating seed." The numb ...

s are usually present. It is the only

cypress Cypress is a common name for various coniferous trees or shrubs of northern temperate regions that belong to the family Cupressaceae. The word ''cypress'' is derived from Old French ''cipres'', which was imported from Latin ''cypressus'', the l ...

species in

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

to release

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametop ...

in the summertime.Lanner, R. 1999. Conifers of California. Cuchama Press. (274 p.)

Taxonomy variations

The more recent classification name ''Hesperocyparis stephensonii'' has been used by botanists of the

United States Department of Agriculture The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of comme ...

, the

University and Jepson Herbaria The University and Jepson Herbaria are two herbaria that share a joint facility at the University of California, Berkeley holding over 2,200,000 botanical specimens, the largest such collection on the US West Coast. These botanical natural hist ...

, and the

since 2010. ''

Hesperocyparis ''Hesperocyparis'' (western cypress) is a genus of trees in the family Cupressaceae, containing North American species otherwise assigned to the genus ''Cupressus''. They are found throughout western North America. Only a few species have wide ra ...

'' is a genus of New World species formerly in ''

Cupressus ''Cupressus'' is one of several genera of evergreen conifers within the family Cupressaceae that have the common name cypress; for the others, see cypress. It is considered a polyphyletic group. Based on genetic and morphological analysis, the ...

'', now a genus of Old World species. ''Cupressus stephensonii'' has sometimes been classified as ''Cupressus arizonica'' subsp. ''stephensonii'', as a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. Not all specie ...

of Arizona cypress (''Cupressus arizonica''), and/or as the

variety Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

''Cupressus arizonica'' var. ''glabra''. It can be hard to distinguish the them, one of the main distinguishing characteristics is the color of the smooth bark on mature trees which varies from pink to grey to pure white, as well as the mature form which tends to be much more spreading than ''C. arizonica''. The listing of ''Cupressus stephensonii'' as a subspecies of ''Cupressus arizonica'' is debatable, further molecular analysis may help define the taxonomy.

References

External links

CalFlora Database: ''Hesperocyparis stephensonii'' (Cuyamaca cypress)
— ''formerly Cupressus stephensoniia''.
Jepson eFlora (TJM2) treatment of ''Hesperocyparis stephensonii''
— 'formerly Cupressus stephensoniia + Cupressus arizonica var. glabra''.
USDA Plants Profile for ''Hesperocyparis stephensonii'' (Cuyamaca cypress)
— ''formerly Cupressus stephensonii + Cupressus arizonica subsp. stephensonii''.
Pacific Southwest Research Stations, Cleveland National Forest King Creek Research Natural Area
— ''with in-situ photos + info.''
UC CalPhotos gallery of ''Hesperocyparis stephensonii''
{{Taxonbar, from=Q539527 stephensonii Endemic flora of California Trees of the Southwestern United States Cuyamaca Mountains Natural history of the California chaparral and woodlands Natural history of the Peninsular Ranges Natural history of San Diego County, California Cleveland National Forest Plants described in 1948 Critically endangered flora of California