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photo1

Foliage, pollen cones and seed cones of a tree in habitat [Tim Ives ©2002].

photo1

Tree, Ash Creek grove [Tim Ives ©2002].

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The largest known specimen [Frank Callahan 2010].

 

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Conservation status

Cupressus macnabiana

A. Murray 1855

Common names

McNab cypress.

Taxonomic notes

Synonymy:

"In the inner north Coast Ranges C. macnabiana and C. sargentii produce the only known natural hybrids in Cupressus (Lawrence et al. 1975)" (Eckenwalder 1993). Syn.: Cupressus nabiana Mast. 1891.

Description

"Shrubby trees to 12 m; crown broadly conical, dense. Bark rough, furrowed, fibrous. Branchlets comblike, 0.5-1 mm diam. Leaves with conspicuous, pitlike, abaxial gland that produces drop of resin, sometimes glaucous. Pollen cones 2-3 × 2 mm; pollen sacs 3-5. Seed cones globose, mostly 1.5-2.5 cm, brown or gray, not glaucous; scales 3-4 pairs, smooth except for erect conic umbos, 2-4 mm. Seeds 2-5 mm, light to medium brown, sometimes slightly glaucous" (Eckenwalder 1993).

"Among all the true Cypresses of North America this one is unique in having flattened branchlets always lying all in one plane, to form a 'spray' ... instead of bristling all around the twig as in most other species of Cupressus" (Eckenwalder 1993).

Distribution and Ecology

USA: California at 300-850 m in chaparral and foothill woodland, often on serpentine (Eckenwalder 1993); also at two locations in southwest Oregon (F. Callahan email 2010.09.28; both locations supported by herbarium collections). Hardy to Zone 8 (cold hardiness limit between -12.1°C and -6.7°C) (Bannister and Neuner 2001). See also (Thompson et al. 1999).

Data from USGS (1999).

Frank Callahan (email 2010.10.22) reports seeing western gray squirrels (Sciurus griseus) collecting the cones of this species, eating a portion of the outer cone, and discarding the rest. He also observed numerous seedlings in the area where this activity was occurring. I believe this is the first report of Cupressus seed being disseminated by squirrels.

Big tree

Frank Callahan (email 2010.1.17) reports a tree in Aukum, CA that is about 116 cm diameter and 13.7 m tall; photo at left. This is bigger than the largest specimen as reported by American Forests, which Frank also discovered, in 1981.

Oldest

Dendrochronology

Ethnobotany

Observations

Peattie (1950) noted its occurrence "Irregularly scattered on the west slopes of the Sierra Nevada (Aukum in Amador County, Grass Valley in Nevada County at about 2500 feet; Texas Hill and Indiana Creek in Yuba County) and ... in the inner northern Coast Ranges at Hough Springs and Reiff in Lake County, and at Aetna Springs, Napa County; also near Ukiah in Mendocino County." Tim Ives (email, 2002.11.17) also notes that it formerly occurred at Whiskeytown, California, at a site since submerged beneath the Whiskeytown reservoir; and near the former Betty May mine in the Clear Creek mining district of Shasta Co. just west of the Whiskeytown grove, near the Shasta/ Trinity Co. line. He adds (e-mail, 2008.10.02) that trees grown from seed from the Whiskeytown grove can be found in the vicinity. One is at the Whiskeytown National Recreation Area visitor center on CA-299, between the visitor center and the highway on a short little trail that goes around behind the visitor center. It is marked with a sign. He also reports that the park botanist has been involved in efforts to outplant seedlings from the original, now submerged Whiskeytown grove at locations throughout the park, and that the area contains several mature trees that were transplanted in the early 1960s from the Whiskeytown grove to homesteads in the vicinity.

Remarks

The epithet honors James McNab (1810-1878), Curator of the Edinburgh Botanic Garden at the time the species was described (Jepson 1923). McNab is now remembered chiefly for his 1834 Mexican collecting trip, from which he successfully introduced the poinsettia. Although the species was described by Andrew Murray, a Scots politician who also made a name for himself studying insects and conifers, it was actually collected by A.F. Beardsley, a professional seed collector working for Mr. Murray. Rogers (1998) provides an engaging sample of some of Beardsley's writing.

Citations

Jepson, W.L. 1923. The Trees of California, ed. 2. Description of C. macnabiana reproduced HERE, courtesy of the Cupressus Conservation Project website.

Rogers, David. 1998. An addendum on the botanical history of Santa Lucia fir, Abies bracteata, with excerpts from the notes and letters of early collectors. Double-Cone Quarterly 1(3). http://www.ventanawild.org/news/ws98/slfirs2.html, accessed 2007.01.01.

See also

Farjon (2005) provides a detailed account, with illustrations.

Griffin and Critchfield (1972).

Herbarium data for all California species are accessible via the CalFlora Database.

Last Modified 2014-12-05