''Hesperocyparis stephensonii'' is a species of

western cypress ''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 ...

known as the Cuyamaca cypress that is found only in one very small area in

Southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural List of regions of California, region that generally comprises the southern portion of the U.S. state of California. Its densely populated coastal reg ...

Distribution

The Cuyamaca Cypress only verifiably exists in the

headwaters The headwater of a river or stream is the geographical point of its beginning, specifically where surface runoff water begins to accumulate into a flowing channel of water. A river or stream into which one or many tributary rivers or streams flo ...

area of King Creek in the

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

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 Pacific Coast Range ...

system, south of

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

within

San Diego County San Diego County (), officially the County of San Diego, is a county in the southwest corner of the U.S. state of California, north to its border with Mexico. As of the 2020 census, the population was 3,298,634; it is the second-most populous ...

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 is a National forest (United States), U.S. national forest in Southern California that encompasses 460,000 acres/ of inland Montane ecosystems, montane regions. It is approximately 60 miles from the Pacific Ocean, withi ...

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 an inventory of the global conservation status and extinction risk of biological ...

Critically Endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

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 c ...

Inventory of Rare and Endangered Plants listed Seriously endangered species. The entire

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 ...

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

Cedar Fire The Cedar Fire was a massive, highly-destructive wildfire, which burned of land in San Diego County, California, during October and November 2003. The fire's rapid growth was driven by the Santa Ana winds, causing the fire to spread at a rat ...

Description

''Hesperocyparis 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 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 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 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 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 ( ; ; "a cavity, small cup, any cup-shaped hollow", gen. (), ) is a "seed leaf" – a significant part of the embryo within the seed of a plant – and is formally defined as "the embryonic leaf in seed-bearing plants, one or mor ...

s are usually present. It is the only

species in

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

to release

pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

in the summertime.

Taxonomy

''Hesperocyparis stephensonii'' was not given a scientific description until 1948. In that year Carl Brandt Wolf published a paper and gave it the name ''Cupressus stephensonii''. At that time it was standard for species classified in ''

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 ...

'' to be classified as part of a larger ''

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 ...

'' genus that covered both new and old world species. Though somewhat distinct there was disagreement on its correct classification with it being described as a

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), ...

of ''

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

'' in 1966 and in 1982 as a

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of the same. In the 2000s new genetic research called into question the classification of New World cypress trees. In 2009 a paper was published by Jim A. Bartel that reclassified most of the North American species into the new genus ''Hesperocyparis''. By the year 2017 this classification was being used by 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,

, and University and Jepson Herbaria. In the past there has been considerable debate about the status of ''Hesperocyparis stephensonii'' as a species and some sources continue to use classifications such as ''Cupressus arizonica'' var. ''stephensonii''. ''Hesperocyparis stephensonii'' is recognized as an accepted species by

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 ...

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 ...

, and the Gymnosperm Database.

Names

Wolf named the species ''stephensonii'' to honor Bert Stephenson, a ranger with the US Forest Service who died in 1944. Ranger Stephenson had noticed the trees on King Creek while fighting a forest fire in the area and informed Wolf about them. The common name "Cuyamaca cypress" comes from its native habitat on Cuyamaca Peak.

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=Q32856063) stephensonii Trees of Northern America 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