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.[2][4][3] It was previously listed as Cupressus arizonica subsp. stephensonii and Cupressus arizonica var. glabra.[2][4]
Trees were reported growing as low as 3,000 feet (910 m) in elevation in 1998, but the presence of these individuals today has not been verified.[6] Most individual trees occur at 4,500–5,100 feet (1,400–1,600 m) within the Pacific Southwest Research Station's King Creek Research Natural Area, in the Cleveland National Forest.[7][4][8]
Cupressus stephensonii trunk — note the very subtle differences in bark color and texture from C. glabra and C. forbesii.
Cupressus stephensonii may attain heights of 10 to 16 m (33 to 52 ft).[7] 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 seeds per cone, not at all glaucous. 3-4 cotyledons are usually present. It is the only cypress species in California to release pollen in the summertime.[4][11]
Cupressus stephensonii has sometimes been classified as Cupressus arizonica subsp. stephensonii, as a subspecies of Arizona cypress (Cupressus arizonica), and/or as the varietyCupressus arizonica var. glabra.[4] It can be hard to distinguish 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 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.
