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Foliage and cones on a specimen at North Carolina Botanical Garden, Chapel Hill [C.J. Earle, 2004.10.27].


Bark on trees that are 15, 30 and 50 cm dbh. Trees at North Carolina Botanical Garden, Chapel Hill [C.J. Earle, 2004.10.27].


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Conservation status

Chamaecyparis thyoides

(Linnaeus) Britton, Sterns, et Poggenburg 1888

Common names

Atlantic white-cedar, southern white-cedar (Michener 1993), white cypress (Dallimore et al. 1967), swamp cedar.

Taxonomic notes

Syn: Cupressus thyoides Linnaeus 1753; Thuja sphaeroidea Spreng.; Chamaecyparis sphaeroidea (Spreng.) Spach.

One subspecies, Chamaecyparis thyoides subsp. henryae (Li H.L.) E. Murray, sometimes treated as a separate species Ch. henryae Li H.L.; syn. Ch. thyoides var. henryae (Li H.L.) Little. Li (1962) segregated the disjunct Gulf Coast populations in Alabama, Florida, and Mississippi as Ch. henryae based on smoother bark, less flattened branchlets, lighter yellowish green foliage, steeper angle of leaf appression to the stem, more prominently keeled but less glandular leaves, and slightly larger cones, seeds, and seed wings. These features contrasted with phenotypes found in the 'northern and mid-Atlantic' populations, and Li proposed a relationship to Cupressus nootkatensis (which at the time was generally assigned to Chamaecyparis) rather than to Ch. thyoides. "Preliminary comparison of herbarium material from the Southeast (including populations in Georgia and Florida) leads to retention of Ch. thyoides as a subtly variable complex with the imperfectly differentiated Ch. henryae at one end of the range" (Michener 1993); although close to typical Ch. thyoides, it is ecologically adapted to greatly different climatic conditions, and field and genetic research is required before the taxon can be dismissed or reduced in status.

"A. J. Rehder (1949) listed, with bibliographic citations, 30 published varieties and forms best considered as cultivars" (Michener 1993).


Trees to 20 m tall and 80 cm dbh. "Bark dark brownish red, less than 3 cm thick, irregularly furrowed and ridged. Branchlet sprays fan-shaped. Leaves of branchlets to 2 mm, apex acute to acuminate, bases of facial leaves often overlapped by apices of subtending facial leaves; glands usually present, circular. Pollen cones 2-4 mm, dark brown; pollen sacs yellow" (Michener 1993). Seed cones maturing and opening the first year, commonly somewhat irregular or asymmetrical, 4-9 mm broad, glaucous, bluish purple to reddish brown, not notably resinous; scales 6-8(10), each scale depressed and minutely mucronate, the apical pair of scales fused. Seeds 1-2 per scale, 2-3 mm, wing narrower than body (Michener 1993, M.P. Frankis pers. obs. 1999.02.03).

In addition to the foliage differences noted above, subsp. henryae differs from the type in having more open growth with less congested branchlets; it also can potentially become a larger tree (c.f. Big Tree) (M.P. Frankis pers. obs. 1999.02.03).

Distribution and Ecology

USA: Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Delaware, Pennsylvania, Maryland, Virginia, North Carolina, South Carolina, Georgia, at 0-500 m, chiefly in bogs and swamps of the Atlantic Coastal Plain (Michener 1993). Subsp. henryae in Florida, Alabama and Mississippi, in bogs and swamps of the Gulf Coastal Plain (Frankis, M.P., personal observations 1999.02.03). See also Thompson et al. (1999). Hardy to Zone 5 (cold hardiness limit between -28.8°C and -23.3°C) (Bannister and Neuner 2001); subsp. henryae zone 8.

Distribution data from USGS (1999). Subsp. thyoides shown in red, subsp. henryi in purple. Points plotted as tree icons represent isolated or approximate locations.

Big tree

Subsp. henryae:height 27 m, DBH 150 cm, crown spread 13 m, located in Brewton, Alabama (American Forests 1996).


Ages exceeding 1000 years are cited, without supporting data (Burns and Honkala 1990).






This page co-edited with M.P. Frankis, 1999.02.

See also

Farjon (2005).

Laderman, Aimlee D. 1989. The ecology of Atlantic white cedar wetlands: a community profile. U.S. Fish and Wildlife Service Biological Report 85(7.21). 114 pp.

Hopton, H.M. and N. Pederson. 2005. Climate sensitivity of Atlantic white-cedar at its northern range limit. Atlantic White Cedar: Ecology, Restoration and Management, Proceedings of the Arlington Echo Symposium. June 2-4 2003. Millersville, MD. USDA For. Ser. Gen. Tech. Rep.

Zimmerman, George. 'Atlantic White-Cedar Initiative', website address This website provides news and announcements, an extensive bibliography, and much additional information on the species.

Last Modified 2014-12-05