Cupressus stephensonii

Cupressus stephensonii is a species of conifer known as the Cuyamaca cypress, and is endemic to southern California. 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 area of King Creek in the Cuyamaca Mountains of the Peninsular Ranges system, south of Cuyamaca Peak within San Diego County in extreme Southern California.
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.
Conservation.
It is an IUCN Red List Critically endangered species, and a California Native Plant Society Inventory of Rare and Endangered Plants listed Seriously endangered species. The entire native (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.
Female cones about 10 mm in diameter, cone scales 6-8, but mostly 6, often, but not always, with conspicuous umbos 3–4 mm high and conical. Seeds average 100-125 per cone, not at all glaucous. Cotyledons 3-4. It is the only California Cypress species to release pollen in the summertime.
Taxonomy variations.
The more recent classification name "Hesperocyparis stephensonii" has been used by botanists of the USDA, University and Jepson Herbaria, and the California Native Plant Society since 2010. "Hesperocyparis" is a genus of New World species formerly in "Cupressus", now a genus of Old World species.
"Cupressus stephensonii" has sometimes been classified as "Cupressus arizonica" subsp. "stephensonii", as subspecies of Arizona cypress ("Cupressus arizonica"), and/or as the variety "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.