Taxodium
Read about Taxodium in the Standard Cyclopedia of Horticulture
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Taxodium (alluding to the similarity of the foliage to that of Taxus). Syn., Glyptostrobus, Schubertia. Pinaceae. Ornamental woody plants, grown chiefly for their graceful feathery foliage. Deciduous or evergreen trees or shrubs: lvs. alternate, linear, usually 2-ranked, falling off in autumn or the second year together with the short lateral branchlets: fls. monoecious, small; staminate fls. catkin-like, consisting of spirally arranged anthers, with 4-9 anther- cells and forming terminal panicles; pistillate fls. solitary or in pairs at the ends of branchlets of the previous year, composed of imbricated scales bearing 2 ovules inside at the base: cone globose or nearly so, maturing the first year, consisting of spirally arranged woody scales enlarged at the apex into an irregularly 4-sided disk with a mucro in the middle and toward the base narrowed into a slender stalk; 2 triangular, winged seeds under each scale; cotyledons 4-9.—Two species in N. Amer. and 1 in China. Of the three species, the only one well known in cultivation is the bald cypress. T. distichum, a tall pyramidal deciduous tree with small linear two-ranked leaves and small globose cones. It is hardy as far north as New England and is a very desirable tree for park planting. Its light green feathery foliage and the narrow pyramidal habit which it usually retains in cultivation give it a very distinct appearance. In its native habitat it forms in old age a broad round-topped head sometimes 100 feet across and has the trunk much enlarged at the base by huge often hollow buttresses projecting in all directions and terminating in long horizontal roots. From these roots spring the peculiar cypress knees, pyramidal protuberances composed of a very light, soft, spongy wood and spongy bark. These sometimes attain a height of 10 feet and with age usually become hollow. From the under side of the horizontal roots large anchor-roots are sent perpendicularly into the earth and help to anchor the tree firmly in the swampy yielding soil. The knees are thought by some to be formed for the purpose of strengthening this root-system, since they are chiefly found opposite to the anchor-roots, but their main purpose is probably to bring air to the roots during the several weeks or months when the swamps are covered with water. The knees always grow high enough to rise above the surface of the water (see, also, G. F. 3, pp. 2, 21, 22, 57). The bald cypress is one of the most valuable timber trees of North America. The wood is brown, light and soft, close and straight-grained, but not strong; it is easily worked, durable in the soil and much used for construction. The bald cypress thrives best in moist sandy soil, but also does well in drier situations. The habit seems to depend somewhat on the degree of moisture; in drier soil the head is more narrow-pyramidal, in moist soil broader and more spreading. Propagated by seeds sown in spring and the varieties by grafting on seedling stock early in spring in the greenhouse; also by cuttings in sand constantly saturated with water or grown in water alone, under glass. T. heterophyllum, Brongn. (Glyptostrobus heterophyllus, Endl.). Shrub, 10 ft. high: lower branches pendulous: lvs. linear and scale-like on the same plant: cones ovoid, 3/4 in. long. China. Tender and rarely cult. Often confounded with varieties of T. distichum.
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 Bald Cypress forest in a central Mississippi lake | ||||||||||||
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| Taxodium ascendens - Pond Cypress Taxodium distichum - Bald Cypress |
Taxodium is a genus of one to three species (depending on taxonomic opinion) of extremely flood-tolerant conifers in the cypress family, Cupressaceae. It is one of several genera in the family that are commonly known as "cypresses". Within the family, Taxodium is most closely related to Chinese Swamp Cypress (Glyptostrobus pensilis) and Sugi (Cryptomeria japonica).
Species of Taxodium occur in the southern part of the North American continent and are deciduous in the north and semi-evergreen to evergreen in the south. They are large trees, reaching 30-45 m tall and 2-3 m (exceptionally 11 m) trunk diameter. The needle-like leaves, 0.5-2 cm long, are borne spirally on the shoots, twisted at the base so as to appear in two flat rows on either side of the shoot. The cones are globose, 2-3.5 cm diameter, with 10-25 scales, each scale with 1-2 seeds; they are mature in 7-9 months after pollination, when they disintegrate to release the seeds. The male (pollen) cones are produced in pendulous racemes, and shed their pollen in early spring.
Species
The three taxa of Taxodium are treated here as distinct species, though some botanists treat them in just one or two species, with the others considered as varieties of the first described. The three are distinct in ecology, growing in different environments, but hybridise where they meet.
- Taxodium distichum - Bald Cypress
The most familiar species in the genus is the Bald Cypress, native to much of the southeastern United States, from Delaware to Texas and inland up the Mississippi River to southern Indiana. It occurs mainly along rivers with silt-rich flood deposits.
- Taxodium ascendens - Pond Cypress
The Pond Cypress occurs within the range of Bald Cypress, but only on the southeastern coastal plain from North Carolina to Louisiana. It occurs in still blackwater rivers, ponds and swamps without silt-rich flood deposits.
- Taxodium mucronatum - Montezuma Cypress
The Montezuma Cypress occurs from the Rio Grande south to the highlands of southern Mexico, and differs from the other two species in being substantially evergreen. A specimen at Santa Maria del Tule in Oaxaca, the Árbol del Tule, is 43 m tall and has the greatest trunk thickness of any living tree, 11.42 m in diameter. It is a riparian tree, occurring on the banks of streams and rivers, not in swamps like the Bald and Pond cypress.
Uses
The trees are especially prized for their wood, of which the heartwood is extremely rot and termite resistant, with the notable exception of the host-specific Pecky Rot fungus (Stereum taxodii), which causes some damaged trees to become hollow and thus useless for timber. "A biochemical called cypressene is believed to act as a natural preservative in the heartwood, but it takes many decades to build up in the wood, making lumber cut from old-growth trees much more resistant to decay than lumber from younger trees". - Sternberg, G., Native Trees for North American Landscapes pp. 476. Bald Cypress wood was much used in former days in southeastern US for shingles. The shredded bark of these trees is used as a mulch, although the current harvest rate for this product is not sustainable and is causing substantial environmental damage especially in the south where cutting boundaries are not being followed.
External links and references
- Gymnosperm Database - Taxodium
- Corkscrew Swamp Sanctuary website
- National Audubon Society, undated. Corkscrew Swamp Sanctuary. A Companion Field Guide. Artype Inc., Ft. Myers. 25 p.
- Sternberg, G., (2004) Native Trees for North American Landscapes pp. 476. Timber Press, Inc.
