References: Hart & Price (1990); Hardin (1971); Watson & Eckenwalder in FNA (1993). Recent studies indicate that the separation of the Taxodiaceae from the Cupressaceae is not warranted (Brunsfeld et al. 1994).1. Leaves opposite or whorled......4
1. Leaves alternate......2
Chamaecyparis Spach (White Cedar) References: Michener in FNA (1993).
Chamaecyparis thyoides (Linnaeus) Britton, Sterns, & Poggenberg, Atlantic White Cedar, Juniper. Cp (NC, SC, VA): peat dome and streamhead pocosins, blackwater stream swamps, hillside seepages, in highly acidic, peaty or sandy soils; uncommon (VA Rare List). March-April; October-November. Chamaecyparis thyoides ranges from s. ME south to n. FL and west to s. MS. From NJ south it is strictly a tree of the Coastal Plain; northwards it is often found in kettle-hole bogs. IN SC and GA, C. thyoides is absent in the outer Coastal Plain, occurring primarily in the fall-line Sandhills. A prized timber tree, now much reduced in abundance, formerly used for cabinetry, boat-building, shingles, and other uses. The wood is valuable enough (and resistant enough to rot) to have been mined from bogs in NJ. NC has some of the largest remaining stands of Atlantic White Cedar, in areas of very difficult access, such as the interiors of major peat-domes and large peat-filled Carolina bays. The species is generally known as "juniper" in our area. The genus consists of 6 species -- ours, 2 in w. North America, and 3 in Japan & Taiwan. [= RAB, C, F, FNA, G, K, S]
Cupressocyparis leylandii (A.B. Jackson & Dallim.) Dallim. & A.B. Jackson, Leyland Cypress, a commonly planted ornamental tree, is a generic hybrid between Chamaecyparis nootkatensis (D. Don) Spach and Cupressus macrocarpa Hartweg.
Cunninghamia R. Brown (China-fir)
*Cunninghamia lanceolata (Lambert) Hooker, China-fir. Pd (NC): escaped from cultivation in forests in urban and suburban areas; rare, introduced from China, reproducing and spreading. A variety of forms are encountered, some with dark-green, others with glaucous-blue foliage. [= K; C. sinensis R. Brown]
Juniperus Linnaeus (Red Cedar, Juniper, Savin)
References: Adams in FNA (1993); Adams (1986); Adams & Demeke (1993).1. Leaves flat-acicular, 5-20 mm long, never scale-like, with a white line on the upper surface; leaves borne in whorls of 3, spreading at 45-90 degrees from the twig; female cone ("berry") axillary, maturing in 2-3 years; [section Juniperus] J. communis var. depressa
1. Leaves primarily scale-like, ca. 1-2 mm long, though acicular and 2-10 mm long on young trees and some lower branches of larger trees, without a white line on the upper surface (though generally somewhat glaucous); leaves of mature twigs borne in opposite pairs of 2, decussate (thus 4-ranked), appressed to the twig (leaves of immature twigs sometimes in whorls of 3, spreading at 10-45 degrees from the twig); female cones ("berries") terminal on short branches, maturing the first year; [section Sabina]...2
2. Female cones ("berries") 4-7 mm long; terminal twigs 0.85-1.00 mm wide (including the scale-like leaves); scale leaves 1.40-1.65 mm long, acute; trees generally with sharply tapered crowns, the lower branches generally ascending J. virginiana var. virginiana
Juniperus communis Linnaeus var. depressa Pursh, Ground Juniper, Mountain Juniper, Common Juniper. Mt (NC, SC, VA), Pd (NC, VA), Cp (SC, VA): in thin soil around rock outcrops on mountain summits and Piedmont monadnocks, high elevation old fields (in VA), xeric Coastal plain sandhills (in SC and VA); rare (NC Candidate, SC Rare List, VA Rare List). March-April; fruit maturing in second or third year. This species is circumpolar, widespread in n. North America, n. Europe, and n. Asia. In North America it is primarily northern and montane, occurring nearly throughout Canada and AK, south in the Appalachians to n. GA, south in the Rocky Mountains to NM, AZ, and CA. Its berry is the juniper berry used as a spice, as well as the main flavoring of gin. It is sometimes planted as a landscaping plant. In e. North America, it is rare and scattered south of PA, MI, and WI, ranging south to a few disjunct sites in VA, NC, SC, GA, and s. IN. As a native species, it is very rare in the Southeast; in NC known only from a few sites, notably Mount Satulah (Macon County) and King's Pinnacle (Gaston County). In SC, a notable population occurs in sandy soils in Aiken County (Hitchcock Woods). Definitely in our area is var. depressa, a decumbent shrub, up to about 1 meter high, forming large clonal patches. Harvill et al. (1992) report scattered sites for var. communis in montane VA; these are based on columnar trees. Adams in FNA (1993) considers var. depressa to be the only variety occurring in e. United States, and states that var. depressa sometimes forms columnar trees to 10 m tall; such individuals may be the basis of reports of var. communis from our area. Additional problems about the status of Juniperus communis in our area remain unresolved; variation in growth form, morphologic characters, and habitat suggest the possibility of the presence of several native taxa. See Coker & Totten (1945) for additional discussion. [= RAB, C, F, FNA, G, K, W; J. sibirica Burgsdorff -- S]
Juniperus virginiana Linnaeus var. silicicola (Small) J. Silba, Southern Red Cedar, Coastal Red Cedar. Cp (NC, SC): maritime forests and scrub, hammocks, brackish marshes, and other sandy, circumneutral situations; uncommon. January-February; October-November. Var. silicicola ranges from e. NC south to s. FL, and possibly west to MS. Many recent authors have treated this taxon as a species, but Adams (1986) and Adams in FNA (1993) consider varietal status more appropriate. The two varieties intergrade in GA. [= FNA, K; Juniperus silicicola (Small) Bailey -- RAB; Sabina silicicola Small -- S; J. virginiana ssp. silicicola (Small) E. Murray]
Juniperus virginiana Linnaeus var. virginiana, Eastern Red Cedar. Pd, Mt, Cp (NC, SC, VA): in a wide variety of forests, pastures, old fields, roadsides, and fencerows, primarily upland, occurring most abundantly on on circumneutral soils (including shrink-swell clays), derived from mafic or calcareous rocks; common (especially in the Piedmont). January-March; October-November. Var. virginiana ranges throughout e. United States. The wood is much used for fenceposts and the traditional southern cedar chest (which takes advantage of the moth-deterrent properties of cedar wood). [= C, F, FNA, G, K; J. virginiana -- RAB, W; Sabina virginiana (Linnaeus) Antoine -- S]
Various species of Juniperus, especially creeping species, are frequently used in landscaping. Molecular studies suggest that section Juniperus (J. communis var. depressa in our area) and section Sabina (J. virginiana in our area) are quite divergent (Adams & Demeke 1993). Small's (1933) recognition of the genus Sabina may prove to be warranted.
Taxodium L.C. Richard (Bald-cypress)
References: Godfrey (1988), abbreviated as Z, Duncan and Duncan (1988), Watson in FNA (1993). Key adapted from Z.1. Leafy branchlets ascending from the twigs, secundly erect (the base often curving, the apical portion of the branchlet borne in a vertical plane), except on juvenile trees (which mimic T. distichum); leaves subulate, spirally arranged, not spreading laterally and featherlike (except on juvemile trees), ascending or appressed; leaves mostly 3-10 mm long (to 15 mm long on juvenile trees); bark thick (1-2.5 cm thick), furrowed, dark-brown, not exfoliating; larger knees short, rarely more than 4 dm tall, usually columnar or broad and mound-like, with thick, compact bark on top; [trees of isolated depressions (clay-based Carolina bays, depression ponds), wet savannas, and, less commonly, blackwater swamps and natural lakes] T. ascendens
1. Leafy branchlets spreading laterally from the twigs, except in the crowns of mature trees (which mimic T. ascendens); leaves linear, flat, spirally arranged but by twisting of their basal portions spreading laterally and featherlike (pseudodistichous), appressed only on drooping branches of the crown, if at all; leaves mostly 8-20 mm long (sometimes less on crown branches); bark thin (less than 1 cm thick), exfoliating in shreddy, orange-brown strips; larger knees often tall, often over 4 dm tall, usually narrowly conical, with thin, shreddy bark on top; [trees of brownwater swamp forests, blackwater swamp forests, natural lakes, and millponds] T. distichum
Taxodium ascendens Brongniart, Pond-cypress. Cp (NC, SC, VA?): limesink ponds (dolines), clay-based Carolina bays, wet savannas, shores of natural blackwater lakes, swamps of blackwater streams; common. March-April; October. T. ascendens ranges from e. NC south to s. FL, west to e. LA; it is surely one of the most scenic trees of eastern North America. Material resembling T. ascendens occurs in se. VA; its taxonomic status is uncertain. [= RAB, G, K, S, Z; T. distichum -- F, in part; T. distichum var. imbricarium (Nuttall) Croom -- FNA; T. distichum var. nutans (Aiton) Sweet]
Taxodium distichum (Linnaeus) L.C. Richard, Bald-cypress. Cp (NC, SC, VA): brownwater and blackwater swamps, usually in riverine situations; common. March-April; October. T. distichum ranges from DE and e. MD south to FL and west to e. TX and se. OK, north along the Mississippi River and its tributaries to s. IN and s. IL. [= RAB, G, K, S, Z; T. distichum var. distichum -- C, FNA; T. distichum -- F, in part only (see also T. ascendens)]
There has been much debate over whether the two taxa of Taxodium in our area should be treated as species or varieties, and if as varieties, the proper nomenclature. I agree with Godfrey (1988), in his preference "to recognize two species ... because it is my perception that the vast majority of trees (populations) are thus distinguishable." At least in our area, true intermediates appear to be non-existent, though the "mimicry" of the two species creates "pseudo-intermediates" that can cause difficulties in identification. Occasionally, as at the junction of Lake Waccamaw and the Waccamaw River (a hybrid habitat) the two species can be seen growing together. There are no intermediates, and with both species present for comparison, even juveniles trees are readily identifiable. Neufeld (1986) discusses the different architecture and ecophysiology of the 2 species.
The only other species in the genus is T. mucronatum Tenore, ranging from s. TX south to Mexico and Guatemala. West of the Mississippi River, the architecture of T. distichum comes to resemble that of T. mucronatum, suggesting the possibility of introgression. For this and other reasons, Watson in FNA (1993) and other authors prefer to treat T. mucronatum as a third variety of T. distichum, T. distichum var. mexicanum Gordon.
Thuja occidentalis Linnaeus, American Arborvitae, Flat Cedar, Northern White Cedar. Mt, Pd (NC, VA): dry limestone, dolostone, and calcareous sandstone cliffs, talus, and bouldefields, rarely in our area in calcareous swamps, also planted and persisting around old homesites and cemeteries (mainly in the Mountains); uncommon (rare in VA Piedmont, rare in NC, where perhaps only introduced). March-April. The species ranges from Nova Scotia, Hudson Bay, and Manitoba south to PA, OH, n. IN, n. IL, and in the mountains to WV, w. VA, and e. TN. This species is alleged by various authors to have occurred as a native species in nw. NC on limestone bluffs in Alleghany, Ashe, and/or Burke counties, but it has not been relocated in this century, and little apparently suitable habitat occurs in NC. [= RAB, C, F, FNA, G, K, S, W]
Platycladus orientalis (Linnaeus) Franco [= Thuja orientalis Linnaeus], Oriental Arborvitae or Tree-of-life, is planted, especially in graveyards. It differs from Thuja occidentalis in having the branchlets flattened in vertical planes (vs. horizontal planes), the seeds wingless (vs. winged). Platycladus is distinct from Thuja.
Flora of the Carolinas and Virginia, Working Draft of 1 January 1997 -- Gymnosperm Key. Alan S. Weakley. The Nature Conservancy, Southeast Regional Office, Southern Conservation Science Department.